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PubMed1983

Assignment of the genes for mouse type I procollagen to chromosome 16 using mouse fibroblast-Chinese hamster somatic cell hybrids.

Somatic cell hybrids between mouse and Chinese hamster fibroblasts have been used to identify the chromosome responsible for the synthesis of both mouse type I procollagen subunit chains (MCOLA1 and MCOLA2). Thirty-one separate hybrid clones and subclones from ten separate hybridization events were isolated in hypoxanthine-aminopterin-thymidine (HAT) selection medium and were used for detailed gene-mapping studies. ELISA and "Western blotting" immunochemical analysis were used to detect the production of mouse type I procollagen in each hybrid clone. Mouse and Chinese hamster chromosomes were identified in each hybrid clone by trypsin-Giemsa banding of metaphase chromosome spreads and by isozyme analysis. We have found that mouse type I procollagen production segregates concordantly with mouse superoxide dismutase-1, previously mapped to mouse chromosome 16, and with the presence of mouse chromosome 16 karyotypically. Western blotting immunochemical analysis of the separated mouse procollagen chains produced by each hybrid line demonstrated that apparently the genes for both subunit chains are located on the same chromosome. These studies, therefore, assign the structural genes for mouse type I procollagen pro alpha 1 (MCOLA1) and pro alpha 2 (MCOLA2) chains to mouse chromosome 16.

Animals↗
PubMed2004

Mouse allergen exposure and mouse skin test sensitivity in suburban, middle-class children with asthma.

BACKGROUND: Exposure to mouse allergen is prevalent in inner-city homes and is associated with an increased risk of mouse skin test sensitivity in inner-city children with asthma. OBJECTIVE: To determine the distribution of mouse allergen and its relationship to mouse skin test sensitivity in a primarily suburban, middle-class population of asthmatic children. METHODS: Children with asthma, 6 to 17 years old, were recruited from 3 pediatric practices located in counties surrounding the city of Baltimore and from 1 practice located within the city limits. Participants underwent skin prick testing and completed a baseline questionnaire. Their homes were inspected, and settled dust samples were collected for allergen analysis. RESULTS: Two hundred fifty-seven of 335 (76.7%) participants resided outside the city, and 53.7% had annual incomes >$50,000. Mouse allergen was detected in 74.9% of bedrooms, and 13.1% were sensitized to mouse. Lower maternal education (odds ratio [OR], 2.17; 95% CI, 1.28-3.67), city residence (OR, 5.39; 95% CI, 2.23-13.02), and higher bedroom cockroach allergen levels (OR, 9.61; 95% CI, 1.17-79.03) were independent predictors of high bedroom mouse allergen. The risk of mouse skin test sensitivity increased with increasing bedroom Mus m 1 exposure (OR, 1.43; 95% CI, 1.04-1.96, with each increase in quartile), and dog skin test sensitivity was a strong independent predictor of mouse skin test sensitivity (OR, 7.23; 95% CI, 3.03-17.22). CONCLUSION: Mouse allergen exposure is common among suburban, middle-class asthmatic children. Increasing bedroom levels of Mus m 1 and dog skin test sensitivity are risk factors for mouse skin test sensitivity.

Adolescent↗
PubMed2000

Mouse allergen. I. The prevalence of mouse allergen in inner-city homes. The National Cooperative Inner-City Asthma Study.

BACKGROUND: Although mouse allergen is a well-defined cause of IgE-mediated hypersensitivity in occupational settings, it has not been well studied in the general population. OBJECTIVE: We sought to determine the prevalence of mouse allergen in inner-city homes. METHODS: A subset of 608 homes from the National Cooperative Inner-City Asthma Study population had dust samples adequate for analysis of mouse allergen. In addition, data regarding the demographics and housing of the subjects were related to the mouse allergen levels. RESULTS: Ninety-five percent of all homes had detectable mouse allergen (Mus m 1) in at least one room, with the highest levels found in kitchens (kitchen: range, 0-618 microg/g; median, 1.60 microg/g; bedroom: range, 0-294 microg/g; median, 0.52 microg/g; television-living room: range, 0-203 microg/g; median, 0. 57 microg/g). By city, 100% of the kitchens in Baltimore had detectable mouse allergen, with the lowest percentage (74%) in Cleveland. Mouse allergen levels correlated among rooms (R = 0.65-0. 75). Forty-nine percent of the homes had reported problems with mice within the last year, and 29% of the homes had evidence of mice in one or more rooms on home inspection and had higher levels of mouse allergen (P =.0001). Higher allergen levels were also associated with evidence of cockroach infestation in any room (P =.006). None of the other subject or housing demographics evaluated were associated with a higher prevalence or level of mouse allergen. CONCLUSIONS: We conclude that mouse allergen is widely distributed in inner-city homes and that cockroach infestation is associated with high mouse allergen levels.

Allergens↗
PubMed1974

Evidence that the AKR murine-leukemia-virus genome is complete in DNA of the high-virus AKR mouse and incomplete in the DNA of the "virus-negative" NIH mouse.

The AKR mouse has a high titer of murine leukemia virus early in life, and virus-negative cells derived from embryos of this mouse strain can be activated to yield murine leukemia virus by treatment with 5-iododeoxyuridine. In contrast to this high-virus strain, the NIH Swiss mouse has a low incidence of leukemia and no murine leukemia virus has been isolated from it (virus-negative). We have investigated this difference between AKR and NIH mice by examining the sequences specific for murine leukemia virus in nucleic acids of these mice. A single-stranded viral-DNA probe synthesized in vitro using murine-leukemia-virus from the AKR mouse contains at least 87% of the sequences present in the 70S viral RNA; most of these sequences are in proportions similar to their content in the 70S RNA. Using this probe in nucleic acid hybridization experiments, we have shown that NIH-mouse-cell DNA and AKR-mouse-cell DNA differ with respect to sequences specific for AKR murine-leukemia-virus: NIH-mouse-cell DNA lacks some of the virus-specific sequences present in AKR-mouse-cell DNA, and there are two distinct sets of virus-specific sequences in AKR-mouse-cell DNA, whereas there is only one set in NIH-mouse-cell DNA.RNA from virus-negative AKR-mouse cells grown in tissue culture contains some, but not all, virus-specific RNA sequences; however, within 48 hr after initiating treatment of these cells with 5-iododeoxyuridine, the complete viral genome is represented in cellular RNA.

Animals↗
PubMed1976

Expression of human and suppression of mouse nucleolus organizer activity in mouse-human somatic cell hybrids.

Most mouse-human somatic cell hybrids show preferential loss of human chromosomes, absence of human 28S ribosomal RNA, and suppression of human nucleolus organizer activity, as visualized by the Ag-AS silver histochemical stain. In contrast, the mouse-human hybrids studied here show preferential loss of mouse chromosomes. The hybrids were made by fusion of HT-1080-6TG human fibrosarcoma cells with BALB/c mouse peritoneal macrophages or strain 129 mouse teratocarcinoma cells. The Ag-AS staining method shows nucleolus organizer activity of chromosomes 13, 14, 15, 21 (rarely), and 22 in the human parent and chromosomes 12, 15, 16 (rarely), and 18 in the BALB/c mouse parent. In the hybrid cells the human nucleolus organizer regions are active, as shown by Ag-AS staining and involvement in "satellite association." The mouse nucleolus organizer regions are not stained by the Ag-AS method even though mouse chromosomes 12, 15, and 18 are present in the BALB/c hybrids and at least one copy of each mouse chromosome is present in the teratocarcinoma-derived hybrids. Thus, in these mouse-human hybrids, unlike those that lose human chromosomes, only human nucleolus organizer activity is expressed, and mouse nucleolus organizer activity is suppressed.

Animals↗
PubMed1987

Introduction of the human pro alpha 1(I) collagen gene into pro alpha 1(I)-deficient Mov-13 mouse cells leads to formation of functional mouse-human hybrid type I collagen.

The Mov-13 mouse strain carries a retroviral insertion in the pro alpha 1(I) collagen gene that prevents transcription of the gene. Cell lines derived from homozygous embryos do not express type I collagen although normal amounts of pro alpha 2 mRNA are synthesized. We have introduced genomic clones of either the human or mouse pro alpha 1(I) collagen gene into homozygous cell lines to assess whether the human or mouse pro alpha 1(I) chains can associate with the endogenous mouse pro alpha 2(I) chain to form stable type I collagen. The human gene under control of the simian virus 40 promoter was efficiently transcribed in the transfected cells. Protein analyses revealed that stable heterotrimers consisting of two human alpha 1 chains and one mouse alpha 2 chain were formed and that type I collagen was secreted by the transfected cells at normal rates. However, the electrophoretic migration of both alpha 1(I) and alpha 2(I) chains in the human-mouse hybrid molecules were retarded, compared to the alpha (I) chains in control mouse cells. Inhibition of the posttranslational hydroxylation of lysine and proline resulted in comigration of human and mouse alpha 1 and alpha 2 chains, suggesting that increased posttranslational modification caused the altered electrophoretic migration in the human-mouse hybrid molecules. Amino acid sequence differences between the mouse and human alpha chains may interfere with the normal rate of helix formation and increase the degree of posttranslational modifications similar to those observed in patients with lethal perinatal osteogenesis imperfecta. The Mov-13 mouse system should allow us to study the effect specific mutations introduced in transfected pro alpha 1(I) genes have on the synthesis, assembly, and function of collagen I.

Animals↗
PubMed1981

Studies with pure mouse Ehrlich ascites tumor interferons alpha and beta: patterns of induction of (2'-5') (A)n synthetase and of a double-stranded RNA-dependent protein kinase in mouse cells and human cells.

The N-terminal sequences of mouse Ehrlich ascites tumor cell IFN beta (35,000-40,000 daltons) and IFN alpha (20,000 daltons) differ in 18 out of 20 positions. Furthermore, these two IFN species show little immunological cross reactivity. We treated mouse L929 cells and human HeLa S3 cells with essentially pure mouse IFN alpha or IFN beta or both at various concentrations and for various lengths of time. From the treated cells we prepared extracts and compared in these the activities of (2'-5')(A)n synthetase, an enzyme that was earlier shown to be induced by partially purified IFN preparations. The effects of treatment of mouse L929 cells with pure IFN alpha or IFN beta on (2'-5') (A)n accumulation in the cell extracts were very similar both in respect to the dependence on the length of exposure of the cells to the IFNs and on IFN concentration. Treatment with both IFN alpha and IFN beta at concentrations resulting in only partial induction of the enzyme led to an additive rather than to a synergistic effect. The maximal level of enzyme induced was the same in cells treated with high concentrations of IFN alpha or IFN beta or both. Mouse IFN alpha was as active as IFN beta in inducing a double-stranded RNA-dependent protein kinase in mouse L cells. The treatment of HeLa S3 cells with IFN beta did not affect the accumulation of (2'-5') (A)n in their extracts whereas treatment with IFN alpha boosted the accumulation though to a lesser extent than in the case of mouse L cells. These results are in line with the finding that mouse IFN alpha can, but mouse IFN beta cannot convert HeLa S3 cells into the antiviral state and also with the more pronounced homology in N-terminal sequence between mouse IFN alpha and a human (lymphoblastoid) IFN chi than between mouse IFN beta and a human IFN beta.

2',5'-Oligoadenylate Synthetase↗
PubMed1987

Differences in biological activity and structural protein VP1 phosphorylation of polyomavirus progeny resulting from infection of primary mouse kidney and primary mouse embryo cell cultures.

Both primary mouse kidney and primary mouse embryo cells in culture were used for polyomavirus progeny production. Examination of polyomavirus virion structural integrity revealed that mouse embryo cell progeny contained a threefold greater population of unstable particles when compared with mouse kidney cell progeny. Differences in biological activity between these two progeny virion types were also shown. Mouse kidney cell progeny compared with mouse embryo cell progeny exhibited a 10-fold greater ability to agglutinate guinea pig erythrocytes, a 3-fold lower ability to become internalized into monopinocytotic vesicles, and a 2-fold lower ability to initiate a productive infection based on positive nuclear immunofluorescence when mouse embryo host cell cultures were used. The mouse kidney progeny were also found to bind to host cells less specifically than the mouse embryo cell progeny. When these two progeny virion types were labeled in vivo with 32P and subjected to isoelectric focusing followed by sodium dodecyl sulfate-polyacrylamide gel electrophroesis in the second dimension, differences in the phosphorylation pattern of the major virus-encoded structural protein VP1 species were observed. It was revealed that species D and E of mouse kidney cell progeny were phosphorylated to the same degree, while mouse embryo cell progeny species E and F were phosphorylated equally. These data suggest that the host cells play a role in modulating the biological activity of the virus by affecting the degree and site-specific phosphorylation of the major capsid protein VP1 which may influence the recognition of virus attachment proteins for specific cellular receptors.

Animals↗
PubMed1990

A molecular and immunochemical characterization of mouse CR2. Evidence for a single gene model of mouse complement receptors 1 and 2.

The relationships between functional, biochemical, and genetic homologues of human and mouse C receptors 1 (CR1) and 2 (CR2) are incompletely understood. We have isolated and characterized a partial mouse CR2 cDNA clone and determined the exon-intron organization of the gene encoding it. Together they predict a form of mouse CR2 highly identical to the 15 short consensus repeat form of human CR2. Strong similarities in genomic organization and exon-intron junctions indicate that this mouse gene and human CR2 are evolutionary homologues. A polyclonal rabbit anti-mouse CR2 fusion protein, BRN-1, was prepared. BRN-1 immunoprecipitates bands of 155 to 160 kDa under nonreducing conditions in mouse CR2 expressing B cell lines. In mouse spleen a doublet of 155 kDa and 190 kDa under nonreducing and 165 and 205 kDa under reducing conditions is recognized by immunoprecipitation and Western blot analysis. Staphylococcus aureus V8 protease maps of these two proteins show many shared bands. Crossed immunoprecipitation using BRN-1 and 7E9, a previously described mAb reported to identify the 190-kDa mouse CR1 and a smaller 150-kDa protein, indicates that both antibodies react with the same proteins. Therefore, by using BRN-1 we have now linked the genetic mouse CR2 to its functional, biochemically characterized gene product. The observation that BRN-1 also recognizes a second 190-kDa mouse protein defined functionally as a homologue of human CR1, and that these proteins have very similar peptide maps, provides strong evidence that these two proteins are expressed by a single mouse CR2/CR1 transcription unit.

Amino Acid Sequence↗
PubMed2001

Permeability of proteins at the blood-brain barrier in the normal adult mouse and double transgenic mouse model of Alzheimer's disease.

The permeability of albumin, insulin, and human A beta 1--40 at the blood-brain barrier (BBB) was determined in the normal adult mouse (B6/SJL) and in the double transgenic Alzheimer mouse (APP, PS1) by using an I.V. bolus injection technique to quantify the permeability coefficient-surface area (PS) product for each protein after correction for the residual plasma volume (V(p)) occupied by the protein in the blood vessels of different brain regions using a second aliquot of the same protein radiolabeled with a different isotope of iodine ((125)I vs (131)I) as a vascular space marker. This technology for quantifying BBB permeability of proteins was adapted from the rat to the mouse and involved catheterizing the femoral artery and vein of the mouse instead of the brachial artery and vein as for the rat. Because of the smaller blood volume in the mouse, serial sampling (20 microl) of blood from the femoral artery of the mouse was performed and directly TCA precipitated to generate a whole blood washout curve for the intact protein. When similar blood sampling techniques were used in the rat, the PS values for albumin and insulin at the BBB were similar in these two species. In the double transgenic mouse, the V(p) values for albumin were significantly increased 1.4- to 1.6-fold in five of six brain regions compared to the normal adult mouse, which indicated increased adherence of albumin to vessel walls. As a result, the PS values were significantly decreased, from 1.4- to 3.2-fold, which likely reflected decreased transport of albumin by passive diffusion. In contrast, insulin, which is taken up into the brain by a receptor-mediated transport mechanism at the BBB, showed no significant difference in the V(p) values but a significant increase in the PS values in four of six brain regions. This suggests a compensatory mechanism in the Alzheimer's transgenic brain whereby there is an increased permeability to insulin at the BBB. Surprisingly, there was no significant difference in the V(p) or PS values for human A beta 1--40 at the BBB in the double transgenic Alzheimer mouse at 24, 32, or 52 weeks of age, when there is both significant A beta levels in the plasma and amyloid burden in the brains of these animals. These data suggest that there is not an alteration in permeability to human A beta 1--40 at the BBB with increasing amyloid burden in the double transgenic Alzheimer mouse. Although these observations suggest structural alterations at the BBB, they do not support the concept of extensive BBB damage with substantial increases in BBB permeability in Alzheimer's disease.

Age Factors↗
PubMed1997

Interaction of the human protein kinase PKR with the mouse PKR homolog occurs via the N-terminal region of PKR and does not inactivate autophosphorylation activity of mouse PKR.

The RNA-dependent protein kinase (PKR) is implicated in the antiviral and antiproliferative actions of interferon. Mutant forms of human PKR display a transdominant behavior when expressed in transfected cells. The potential for the human PKR protein to physically interact with the mouse PKR homolog has therefore been examined. The yeast two-hybrid system was used to probe the association between mouse and human PKR proteins as measured by activation of two Gal4-responsive reporter genes, HIS3 and IacZ. Expression of full-length wild-type mouse PKR(1-515)WT as a Gal4 fusion protein did not exhibit the growth suppression phenotype in yeast characteristic of wild-type human PKR(1-551)WT. Coexpression of mouse PKR(1-515)WT as a Gal4 DNA-binding domain fusion with either the catalytic-deficient human PKR(1-551) K296R mutant, the RNA-binding-deficient human PKR(1-551)K64E/K296R double mutant, or wild-type mouse PKR(1-515)WT as full-length PKR-Gal4 activation domain fusions resulted in activation of the HIS3 and lacZ reporters. The N-terminal RNA-binding region of human PKR, both WT and the K64E RNA-binding-deficient mutant, also interacted with mouse PKR(1-515)WT sufficiently to activate the reporters but the human catalytic region did not. Mouse and human full-length PKR proteins expressed as glutathione S-transferase (GST) fusions in Escherichia coli were purified on Sepharose beads. Using GST-PKR fusion chromatography, direct physical interaction between the mouse and human PKR homologs was established. Intraspecies PKR interactions were more efficient than interspecies PKR interactions, and interactions between RNA-binding-sufficient PKR proteins were more efficient than those involving an RNA-binding mutant as measured by binding to GST-PKR protein Sepharose beads. The N-terminal region of human PKR within amino acids 1-184 was sufficient for binding mouse PKR. Purified mouse full-length PKR(1-515)WT GST fusion protein retained kinase activity on Sepharose beads, but the activity was not impaired by association with either the full-length or the N-terminal region of human PKR.

Animals↗
PubMed1981

DNA-mediated transfer of the mouse gene for hypoxanthine phosphoribosyltransferase into cultured mouse cells: no integration of the transferred gene at its homologous site in the host genome.

An established Chinese hamster cell line was fused with microcells isolated from phenotypically stable transferent mouse cells which contained a mouse transgenome coding for an abnormal form of mouse hypoxanthine phosphoribosyltransferase (HPRT, EC. No. 2.4.2.8) (Willecke et al. 1979). Two hybrids were isolated which expressed the abnormal form of mouse HPRT but no mouse alpha-galactosidase (GALA, EC. No. 3.2.1.22). In one of these microcell hybrids the abnormal HPRT activity segregated under counter-selective conditions with mouse chromosome 3. No mouse chromosome or additional mouse gene marker was found in the second microcell hybrid, possibly because of breakage and/or rearrangement of the integrated transgenome during the isolation of this hybrid. We conclude from these results that the transferred mouse HPRT gene is a phenotypically stable clone is not integrated at its homologous site on the host X chromosome. Rather, the transgenome is probably integrated into mouse chromosome 3, possibly due to homologies in repeated DNA sequences which may occur in the transgenome and which are interspersed at many sites in the host genome.

Animals↗
PubMed1995

Phenytoin covalent binding and embryopathy in mouse embryos co-cultured with maternal hepatocytes from mouse, rat, and rabbit.

The anticonvulsant drug phenytoin is teratogenic in a variety of species including humans. Traditional embryo culture studies have employed the addition of 9000 g supernatant (S-9) or microsomal fractions from induced rat or mouse liver as an exogenous bioactivating system to approximate a maternal contribution. However, cellular fractions, unlike cultured intact hepatocytes, may themselves be embryotoxic, and do not reflect the in vivo balance of bioactivation and detoxification. To evaluate in vitro the known in vivo differential species susceptibility to phenytoin teratogenesis, day 9.5 (day of plug = day 1) mouse embryos either were cultured alone for 24 hr or were co-cultured with hepatocytes from maternal mice, rats or male rabbits, thereby exposing the embryos to the effects of potential species-specific phenytoin metabolism. In the absence of hepatocytes, phenytoin embryotoxicity was concentration dependent (0, 10, 20 and 60 micrograms/mL), with decreases in embryonic growth, reflected by reduced yolk sac diameter and crown rump length, apparent within the maternal therapeutic range (20 micrograms/mL). Covalent binding of the radiolabeled drug to live embryonic tissue was significantly higher than in control embryos previously killed by fixation, suggesting that the embryo can bioactivate phenytoin to a toxic reactive intermediate. Mouse embryos grew equally well with hepatocytes from all three species, indicating interspecies tissue compatibility. The addition of rat and rabbit hepatocytes, but not mouse hepatocytes, significantly enhanced the phenytoin-induced impairment of mouse embryonic development, as demonstrated by reductions in somite number. The phenytoin-induced impairment of mouse embryonic growth was not enhanced by the addition of rat or rabbit hepatocytes, while mouse hepatocytes conferred protection. The covalent binding of phenytoin to extracellular proteins in the culture medium was not enhanced by the addition of mouse hepatocytes. These results suggest that mouse embryos intrinsically can bioactivate phenytoin to a toxic reactive intermediate, with embryopathic consequences. The protection conferred by maternal mouse hepatocytes suggests a species-specific maternal biochemical balance favouring detoxification that is not shared by rat and rabbit hepatocytes, which enhanced phenytoin embryopathy. Thus, while phenytoin teratogenicity likely involves embryonic bioactivation, maternal determinants may contribute variably to teratologic susceptibility in a species-specific manner.

Animals↗
PubMed1986

Antibody against mouse liver 5'-nucleotidase immunostains white matter in the adult mouse central nervous system.

An antiserum against rat liver 5'-nucleotidase has been shown to immunostain myelinated fibers and oligodendrocytes in the rat CNS, consistent with evidence for 5'-nucleotidase activity in rat brain myelin and oligodendrocytes (Cammer, Sacchi and Kahn, Devel. Brain Res., 1985, 20: 89-96). However, in the mouse CNS, in which myelin also has 5'-nucleotidase activity, that antiserum stained only blood vessels. To obtain an antibody against the mouse enzyme, 5'-nucleotidase was partly purified from mouse liver membranes by detergent extraction, heat treatment, affinity chromatography, acidification, and ammonium sulfate fractionation. The preparation, which was enriched about 110-fold in 5'-nucleotidase specific activity, compared to the starting extract, was electrophoresed on a preparative slab gel containing Triton X-100, a strip was stained histochemically for 5'-nucleotidase, and the material corresponding to the stained band was used to immunize a rabbit. The immune IgG fraction, but not the preimmune IgG, reacted with mouse brain homogenates. The immune serum gave consistently greater inhibition of 5'-nucleotidase activity in mouse liver homogenates, mouse brain myelin and mouse brain homogenates, but not rat brain or liver homogenates, compared to the preimmune serum. The immune serum, but not the preimmune serum, immunostained white matter in the normal adult mouse brain and spinal cord. The findings suggest that the mouse may have one isozyme of 5'-nucleotidase similar to that in rat with respect to subunit sizes but differing in primary structure at one or more antigenic sites and support previous observations of 5'-nucleotidase activity in myelin from mouse brains and spinal cords.

5'-Nucleotidase↗
PubMed1994

Distribution of airborne mouse allergen in a major mouse breeding facility.

BACKGROUND: Occupational allergy to mice is a major cause of disability among workers in mouse breeding and research facilities. Efforts to prevent and treat allergy require a detailed knowledge of exposure levels to allergen. OBJECTIVE: This study was designed to quantitate the level of major mouse allergen (Mus m I) in central room air and immediate breathing zones under a variety of working conditions. METHODS: An Andersen sampler (Groseby Andersen, Spirotech Div., Atlanta, Ga.) was used to collect allergen in each room. A Gillian Personal sampler (Gillian Instrument Corp., West Caldwell, N.J.) collected particles in the worker breathing zone. ELISA was used to quantitate the concentration of Mus m I collected on the two collection devices. RESULTS: Total Mus m I recovered from Andersen samplers ranged from 0.2 to 1.5 ng/m3 in rooms without mice and 0.5 to 15.1 ng/m3 in rooms with mice. Allergen recovered from the zone of worker activity ranged from 1.2 to 2.7 ng/m3 in rooms without mice and from 16.6 to 563.0 ng/m3 in rooms with mice. Direct mouse contact was associated with the highest levels of exposure to Mus m I. Analysis revealed the bulk of allergen to be in mid-particle size ranges (3.3 to 10 microns) for mouse-containing rooms and in small particle size range (0.43 to 3.3 microns) for non-mouse-containing rooms, suggesting that small particles were carried along corridors from rooms with mice into non-mouse-containing rooms. Ventilation characteristics of rooms and mouse population density were evaluated with a "mouse loading" index (number of mice per cubic meter of ventilated air per hour). Mouse loading correlated strongly with small particles (< 3.3 microns) in ambient air. CONCLUSIONS: Mus m I is widely distributed within mouse breeding facilities. Direct worker contact with mice seems to be the major factor in high level exposure.

Air Pollutants, Occupational↗
PubMed2003

Genomic sequence analysis of the mouse desmoglein cluster reveals evidence for six distinct genes: characterization of mouse DSG4, DSG5, and DSG6.

The desmosomal cadherins, comprising the desmogleins and desmocollins, are calcium-dependent transmembrane adhesion molecules that are essential for the cell adhesive role of desmosomes. Until recently, three mouse and three human desmoglein isoforms had been characterized that are expressed in a tissue- and differentiation-specific manner. Very recently, however, we revealed genetic evidence for the presence of a fourth human gene, DSG4. Here we present genetic evidence for the mouse DSG4 homolog as well as two additional novel mouse desmoglein genes situated within the mouse cluster. We have named these two new genes DSG5 and DSG6, both of which demonstrate close homology with mouse DSG1. Mouse DSG4 comprises 16 exons spanning 36 kb of 18q, whereas DSG5 and DSG6 comprise 15 exons spanning approximately 33 kb and 37 kb, respectively, of 18q. The mouse desmoglein 4 transcript contains an open reading frame of 3123 bp, encoding a precursor of 1041 amino acids. The desmoglein 5 transcript contains an open reading frame of 3180 bp encoding a precursor of 1060 amino acid residues, and the desmoglein 6 transcript contains an open reading frame of 2733 bp encoding a precursor of 911 amino acid residues. Using mouse tissue cDNA we have demonstrated that mouse desmogleins 4, 5, and 6 are all expressed in the epidermis but are expressed during different times of mouse development.

Amino Acid Sequence↗
PubMed1993

Dose-dependent ras mutation spectra in N-nitrosodiethylamine induced mouse liver tumors and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone induced mouse lung tumors.

In a previous study, the spectrum of H-ras mutations detected in B6C3F1 mouse liver tumors induced by 5, 50 or 150 mumol/kg body wt of N-nitrosodiethylamine (NDEA) was similar to that in spontaneous B6C3F1 mouse liver tumors, suggesting that activation of the H-ras gene in NDEA-induced mouse liver tumors may not be the direct result of the chemical interaction with the H-ras gene. In the present study, mutations in the H-ras oncogene from B6C3F1 mouse liver tumors induced by 5 or 50 mumol/kg body wt of NDEA were characterized by DNA amplification with polymerase chain reaction (PCR), single-strand conformation of polymorphism (SSCP) and direct sequence analysis. Twenty-one of 66 NDEA-induced B6C3F1 mouse liver tumors contained activated H-ras gene with 2 of 21 having a CG to AT transversion at the first base of codon 61, 17 of 21 having AT to GC transition and 2 of 21 having an AT to TA transversion at the second base of codon 61 in the H-ras gene. The predominant mutation, AT to GC transition (17/21, 81%) is consistent with the formation of O4-ethylthymine adduct, and is distinct from the predominant CG to AT transversion (50%) at the first base of codon 61 detected in H-ras gene from NDEA-induced B6C3F1 mouse liver tumors in a previous study by Stowers et al. Mutations in the K-ras oncogene from 59 A/J mouse lung tumors induced by 0.53 mmol/kg body wt of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were also characterized by using the above mentioned methods. Forty-six of 59 NNK-induced A/J mouse lung tumors contained activated K-ras genes. All 46 (100%) of the activated K-ras gene had GC to AT transitions at the second base of codon 12. The same mutation was observed in 70% (7/10) of the K-ras oncogene from A/J lung tumors induced by 4.8 mmol/kg body wt (given in 21 doses) of NNK. These data suggest that other factors in addition to genotoxic effect might be involved in the induction of rodent tumors by some carcinogens when given at higher doses. Therefore, further studies to compare the dose-dependent differences in the profile of ras mutations induced by chemical carcinogens may help to assess human cancer risk. Mutation(s) in exons 5-8 of the p53 gene was not found in these NDEA-induced mouse liver tumors and NNK-induced mouse lung tumors.

Animals↗
PubMed1994

Absence of autoantibodies against glutamate decarboxylase (GAD) in the non-obese diabetic (NOD) mouse and low expression of the enzyme in mouse islets.

GAD is a major islet cell autoantigen in human type 1 diabetes mellitus. Autoantibodies are preferentially directed against the 65-kD isoform of the enzyme which is the only form expressed in human islets of Langerhans. The NOD mouse is a spontaneous model of type 1 diabetes, frequently employed in studies dealing with the immunopathogenesis of the disease. In the present study the reactivity of sera from 34 prediabetic and 15 diabetic NOD mice was tested against GAD protein present in islets of Langerhans and cerebellum, and against recombinant, semi-purified GAD-65 and GAD-67. A rabbit antiserum (K2) raised against GAD-67 could readily recognize the recombinant GAD-67 and the isoform present in rat and mouse islets and mouse brain. A MoAb (GAD-6) specific for the GAD-65 isoform reacted against the recombinant GAD-65 and the isoform present in rat islets and mouse brain, whereas no reactivity was observed when using mouse islets. However, when testing the NOD mice sera by immunohistochemistry, immunoprecipitation and Western blot, no reactivity against any of the isoforms of GAD could be detected. Using reverse transcription polymerase chain reaction (PCR), GAD-67 mRNA could be detected in mouse and rat islets and in mouse brain. GAD-65 mRNA could also be detected in rat islets and mouse brain, but apparently a much lower copy number is present in mouse islets. These findings stress important differences in the immune response occurring in the animal model NOD mouse compared with human type 1 diabetes, and emphasize that human and animal type 1 diabetes possibly represent the final outcome of several different etiological factors.

Animals↗