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At least 19 recordsLinked to original sources

Germ-line reinsertions of AKR murine leukemia virus genomes in Akv-1 congenic mice.

Congenic mouse strains NIH,Akv-1 and NIH,Akv-2 carry the two high ecotropic virus-inducing loci of the AKR mouse on the NIH Swiss genetic background. Progeny tests of animals in three separate congenic families show that both Avk-1 and Akv-2 are stably transmitted as classical mendelian loci in these mice. However, during the process of inbreeding, additional chromosomal viral loci were detected in several NIH.Akv-1 sublines. These loci appeared only in the progeny of virus-positive females. They segregate with mendelian ratios, are unlinked to markers on chromsome 7 near Akv-1, and are phenotypically expressed as high-virus-inducing loci. The generation of new loci for viurs induction, no doubt resulting from the rare germ-line reintegration of the endogenous ectropic provirus, represents a unique form of gene duplication and rearrangement.

AKR murine leukemia virus↗

Are Sinc and the PrP gene congruent? Evidence from PrP gene analysis in Sinc congenic mice.

Congenic mouse strains VM/Dk and VM-Sincs7/Dk differ at the Sinc gene, which controls the incubation period of scrapie in mice; VM/Dk mice are Sincp7p7 and VM-Sincs7/Dk mice are Sincs7s7. Restriction fragment length polymorphism and DNA sequencing analysis demonstrated that the PrP genes also differ in these strains, confirming the close genetic linkage of Sinc and PrP. Using the restriction enzyme HhaI, we have shown that at least 100 kb of DNA flanking the PrP gene differs between the two strains, and therefore the congruence of the Sinc and PrP genes is still not certain.

Animals↗

Hydrocortisone-induced embryotoxicity and embryonic drug disposition in H-2 congenic mice.

Congenic mouse strains C57BL/10Sn (B10) and B10.A/SgSn (B10A), genetically different only in the region of the H-2 complex, were compared for sensitivity to hydrocortisone-induced embryotoxicity and embryonic drug disposition. Pregnant B10A mice dosed intramuscularly with 0, 100, 150, and 200 mg hydrocortisone/kg body weight and B10 mice injected with 0, 200, 400, 600, and 800 mg/kg, both on gestational day (GD) 12, were evaluated on GD 18 for reproductive toxicity. The induction of cleft palate demonstrated a linear dose-response by probit analysis: The ED50s were 143.6 mg/kg and 512.0 mg/kg for B10A and B10 mice, respectively. Comparison of fetal weight revealed statistically significant intrauterine growth retardation at all doses administered to B10 mice. However, growth retardation was shown only in the high-dose group in the B10A strain. Embryonic drug concentrations were evaluated by administration of hydrocortisone to mice of both strains on GD 12, at the ED50 for cleft palate production in the B10A strain, with 3H-hydrocortisone (5 muci/mouse) added as a tracer. Maternal serum and embryos were analyzed for steroid content. Disposition and pharmacokinetics of 3H-hydrocortisone were similar in both strains, with the majority of serum radioactivity recovered as hydrocortisone and the major radioactive peak in embryos comigrating with cortisone. The results indicate that H-2 haplotype does not influence hydrocortisone-induced cleft palate sensitivity through an alteration of embryonic drug exposure.

Animals↗

NOD.c3c4 congenic mice develop autoimmune biliary disease that serologically and pathogenetically models human primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is an autoimmune disease with a strong genetic component characterized by biliary ductular inflammation with eventual liver cirrhosis. The serologic hallmark of PBC is antimitochondrial antibodies that react with the pyruvate dehydrogenase complex, targeting the inner lipoyl domain of the E2 subunit (anti-PDC-E2). Herein we demonstrate that NOD.c3c4 mice congenically derived from the nonobese diabetic strain develop an autoimmune biliary disease (ABD) that models human PBC. NOD.c3c4 (at 9-10 wk, before significant biliary pathology) develop antibodies to PDC-E2 that are specific for the inner lipoyl domain. Affected areas of biliary epithelium are infiltrated with CD3+, CD4+, and CD8+ T cells, and treatment of NOD.c3c4 mice with monoclonal antibody to CD3 protects from ABD. Furthermore, NOD.c3c4-scid mice develop disease after adoptive transfer of splenocytes or CD4+ T cells, demonstrating a central role for T cells in pathogenesis. Histological analysis reveals destructive cholangitis, granuloma formation, and eosinophilic infiltration as seen in PBC, although, unlike PBC, the extrahepatic biliary ducts are also affected. Using a congenic mapping approach, we define the first ABD (Abd) locus, Abd1. These results identify the NOD.c3c4 mouse as the first spontaneous mouse model of PBC.

Adoptive Transfer↗

Ahr locus phenotype in congenic mice influences hepatic and pulmonary DNA adduct levels of 2-amino-3-methylimidazo[4,5-f]quinoline in the absence of cytochrome P450 induction.

The potent food mutagen/carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) undergoes metabolic N-hydroxylation by cytochromes P450, including cytochrome P450 1A2, followed by generation of an unstable ester catalyzed by acetyltransferases; promutagenic DNA adducts result. Genetic polymorphisms in these enzymes have been implicated in human cancer risk related to arylamine exposure. We investigated the effects of Ahr locus and acetylator polymorphisms on 32P-postlabeled IQ/DNA adducts in lungs and livers of female C57BL/6 mice congenic for slow acetylation and/or Ahr-nonresponsiveness; some groups were pretreated with beta-naphthoflavone (beta NF), a cytochrome P450 1A inducer. Total adducts in lung were doubled by beta NF pretreatment in Ahr-responsive mice only and consisted of < or = 30% adduct 2 and < or = 60% adduct 3. In contrast, in Ahr-nonresponsive mice, adducts 2 and 3 were each < or= 7% of the total. Livers of noninduced Ahr-responsive mice formed 6-18-fold more adducts than those of nonresponsive mice. This striking difference was not due to altered levels of cyp1a-2, as indicated by specific enzyme assays and immunoblotting, and was not accompanied by a comparable increase in the ability of liver preparations to activate IQ to a mutagen in the Ames test. Pretreatment of responsive mice with beta NF to induce cyp1a-1 and cyp1a-2 led to a reduction in liver adduct levels. Acetylation phenotype also had a significant effect in Ahr-responsive mice, with 3-fold more adducts in slow than in rapid acetylators. These results indicate that in uninduced mice, the normal Ah receptor facilitates formation of IQ/DNA adducts in liver and alters the profile of adducts in lung, via an unknown mechanism, whereas the Ah receptor-dependent enzyme induction reduces adducts in liver, probably due to increased detoxification, but increases them in lung.

Acetylation↗

Effects of H-2 and vitamin A on eye defects in congenic mice.

Pregnant mice congenic with C57BL/10 (B10.A, B10.BR, B10.D2, B10.A(2R), B10.A(5R), B10.A(15R), B10.A(1R), B10.A(18R), and B10.OL) were fed Purina Mouse Chow or the same diet plus 200 IU of vitamin A daily. The pregnant dams were sacrificed on the 18th day of gestation and the fetuses were sexed and examined for defects in eye development. It was found that the frequency of microphthalmia and anophthalmia in the female progeny of mice fed Mouse Chow was 7.4-9.2% in B10.A and B10.BR, 4.0-5.5% in B10.A(18R), B10, B10.A(5R), B10.A(1R), B10.A(15R), and B10.A(2R), and 0.8% and 1.4% in B10.D2 and B10.OL mice, respectively. On average, the frequency of these defects in the female progeny was 6.2 times greater than that in males (P less than 0.001). The right eye was 5.8 times more often affected than the left (P less than 0.001). The addition of vitamin A to the diet increased the frequency of these eye abnormalities in all strains, suggesting that this effect is not mediated by loci associated with H-2, as is the case with vitamin A-enhanced cleft palate. The addition of vitamin A to the diet did not affect the ratios of affected males to females, affected right to left eye, or microphthalmia to anophthalmia. The results suggest that there are two loci on chromosome 17, one centromeric to E beta and one telemeric to C4, that interact to determine to some degree the frequency of microphthalmia and anophthalmia.

Animals↗

DNA adducts of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in colon, bladder, and kidney of congenic mice differing in Ah responsiveness and N-acetyltransferase genotype.

Heterocyclic amines, suspected as cancer initiators, require metabolic activation to exert genotoxicity. The food carcinogen 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ) undergoes activation via N-hydroxylation by cytochrome P450 1A2, followed by O-esterification by N-acetyltransferase. We examined the effects of the Ah locus and acetylator polymorphisms (implicated in human colon and bladder cancer risk) on levels of 32P-postlabeled IQ-DNA adducts in C57BL/6 mice congenic for slow acetylation and/or Ah nonresponsiveness. Some were pretreated with beta-naphthoflavone (beta NF), an inducer of cytochromes P450 1A. Guanine adducts were detected in all organs, the predominant one corresponding to N2-(deoxyguanosine-8-yl)-IQ. In the kidney, beta NF pretreatment reduced total adducts by 50% in Ah-responsive animals (P = 0.021); the Ah or acetylator phenotype did not otherwise affect total adducts. In the colon of Ah-nonresponsive animals, rapid acetylators had 3-fold more adducts than slow acetylators (P = 0.0001, vehicle-pretreated; P = 0.0031, beta NF-pretreated). In Ah-responsive mice of either acetylator phenotype, beta NF pretreatment reduced total adducts in the colon by 70% (P = 0.0003). A significant interaction of phenotypes occurred in the bladder; beta NF-pretreatment caused a 2.5-fold increase in adducts but only in the Ah-responsive, rapid acetylator mice. In sum, these polymorphisms influenced the level of IQ-DNA adducts in the kidney, urinary bladder, and colon in complex ways.

Acetylation↗

Variation in p30-related proteins in gross virus-induced tumor cell lines derived from H-2 congenic mice.

p30-related proteins were examined in three in vitro--passaged Gross virus--induced cell lines derived from mice congenic at the H-2 complex: BALB.K-gv-1 (H-2k) (BkGV1), which produces infectious, oncogenic virus, and BALB.B-gv-1 (H-2b) (BbGV1) and BALB/c-gv-1 (H-2d) (BdGV1), which stopped producing infectious virus early in their passage history. The producer BkGV1 line made p30 and its expected precursors. BbGV1 and BdGV1 cells had multiple changes in p30-related protein expression. BbGV1 cells (i) synthesized a truncated gag precursor polyprotein of ca. 47 kilodaltons, (ii) expressed fewer p30-related molecules per cell on their surface than BkGV1 cells, (iii) produced functional reverse transcriptase, and (iv) budded morphologically mature virions which were neither infectious nor oncogenic. BdGV1 cells (i) produced no p30 but expressed some high-molecular-weight proteins with p30 determinants, (ii) expressed fewer p30-related determinants on their surface than BbGV1 cells, and (iii) harbored immature intracisternal viral particles (type A) but did not exhibit budding virions.

AKR murine leukemia virus↗

Effects of H-2 and vitamin A on micrognathia in congenic mice.

Pregnant mice congenic with C57BL/10 (B10.A, B10.BR, B10.D2, B10.A(2R), B10.A(5R), B10.A(15R), B10.A(1R), B10.A(18R), and B10.OL) were fed Purina Mouse Chow or the same diet plus 200 IU of vitamin A daily. The pregnant dams were sacrificed on the eighteenth day of gestation, and the fetuses were sexed and examined for defects in mandibular development. On average, micrognathia occurred five times more frequently in female (1.5%) than male (0.3%) fetuses. The addition of vitamin A to the diet affected only females, reducing the frequency of this defect to that observed in males from dams fed the control diet. Micrognathia was strongly associated with micro- or anophthalmia, but not with defects of the palate. C57BL/10 fetuses had the highest frequency of micrognathia (3.2%) and B10.D2 and B10.A(5R) fetuses had the lowest (0.1%). The results suggest that a locus distal to C4 and perhaps proximal to Qa-1 may exert a moderate influence on mandibular development and a second locus proximal to E beta may have a weak effect.

Alleles↗

Effects of H-2 on neural tube defects in congenic mice.

Pregnant mice congenic with C57BL/10 (B10.A, B10.BR, B10.D2, B10.A[2R], B10.A[5R], B10.A[15Rd, B10.A[1R], B10.A[18R], and B10.0L) were fed Purina Mouse Chow or the same diet plus 200 IU of vitamin A daily. The pregnant dams were sacrificed on the eighteenth day of gestation, and the fetuses were sexed and examined for defects in neural tube development. The frequency of neural tube defects was low (mean frequency of all strains, 0.36%) and was not affected by the addition of vitamin A (200 IU/day) to the diet. Twenty-seven of the 29 defects observed occurred in the anterior tube (exencephaly); fourteen were identified in female fetuses, but the sex could not be determined in the other 15 cases because of fetal death and early autolysis. Variations in frequency among the strains suggest that a locus between E beta and H-2D has a moderate influence on the occurrence of neural tube defects. Strains that had H-2d alleles in this segment of the H-2 complex had relatively high frequencies, and those with H-2b or H-2k alleles had significantly lower frequencies.

Animals↗

Multiparameter analyses of spontaneous nonthymic lymphomas occurring in NFS/N mice congenic for ecotropic murine leukemia viruses.

Mouse strains congenic for ecotropic retrovirus genes have a much higher frequency of spontaneous lymphomas than the background NFS/N strain. In this study, most of these lymphomas have been identified as B-cell in origin by morphologic features, identification of immunoglobulin class, and cell-surface antigens. The classification suggested by Pattengale and Taylor proved to be applicable to the lymphomas studied. Most were of large follicular center cells and are considered typical of the type formerly designated as "reticulum cell sarcoma, type B." Many lymphomas contained a large proportion of nonneoplastic cells which partially obscured their neoplastic component. The role of ecotropic murine leukemia viruses as etiologic agents for B-cell lymphomas remains equivocal. However, because the only difference between the NFS/N and congenic mice is the expression of viruses in the latter, it appears that these viruses are somehow involved in induction of B-cell lymphomas.

Animals↗

Transplantation of skin from human immunodeficiency virus type 1-transgenic mice to normal congenic mice results in graft rejection.

Skin from mice transgenic (Tg) for part of the human immunodeficiency virus type 1 (HIV-1) genome was transplanted onto normal mice of the same strain. All Tg grafts were rejected within 29 days. In contrast, skin from normal mice that was transplanted to HIV-1-Tg recipients remained viable for > 67 days. Histologic examination of Tg grafts on normal mice showed evidence of monocytic infiltrates. Monocytic infiltrates were not observed, however, when either normal or Tg skin was transplanted onto Tg mice. Immunohistologic staining verified the presence of gp120 protein expression in the Tg-transplanted skin but not in adjacent normal skin. It is concluded that the Tg mice are immunologically tolerant to the HIV-1 gene products they express.

Animals↗

Genetic regulation of early survival and cyst number after peroral Toxoplasma gondii infection of A x B/B x A recombinant inbred and B10 congenic mice.

Genetics of two traits, survival and brain cyst number after peroral Toxoplasma gondii infection, were studied by using recombinant inbred strains of mice derived from resistant A/J (A) and susceptible C57BL/6J (B) progenitors, F1 progeny of crosses between A/J and C57BL/6J mice, and congenic mice (B10 background). Analysis of strain distribution pattern of survival of A x B/B x A recombinant mice indicated that survival is regulated by a minimum of five genes. One of these genes appears to be linked to the H-2 complex and another is related to an as yet unmapped gene controlling resistance to Ectromelia virus. Associations of defined traits with resistance or susceptibility to Toxoplasma cyst formation were also analyzed. Cyst number is regulated by a locus on chromosome 17 within 0 to 4 centimorgans of the H-2 complex (p = 0.001). Mice with the H-2a haplotype are resistant and those with the H-2b haplotype are susceptible. This analysis also indicated that the Bcg locus on chromosome 1 may effect cyst number (map distance = 12 centimorgans, p = 0.05). Resistance to cyst formation is a dominant trait. To analyze relative roles of H-2 and Bcg loci on cyst numbers, C57BL10 (B10)-derived congenic strains of mice with known H-2 and Bcg type were studied. These studies indicated that the H-2 complex locus has the primary effect on cyst number.

Administration, Oral↗

Normal hypermutation in antibody genes from congenic mice defective for DNA polymerase iota.

Several low fidelity DNA polymerases participate in generating mutations in immunoglobulin genes. Polymerase eta is clearly involved in the process by causing substitutions of A:T base pairs, whereas polymerase iota has a controversial role. Although the frequency of mutations was decreased in the BL2 cell line deficient for polymerase iota, hypermutation was normal in the 129 strain of mice, which has a natural nonsense mutation in the Poli gene. It is possible that the mice compensated for the defect over time, or that polymerase eta substituted in the absence of polymerase iota. To examine polymerase iota in a genetically defined background, we backcrossed the 129 nonsense mutation to the C57BL/6 strain for six generations. Class switch recombination and hypermutation were studied in these mice and in congenic mice doubly deficient for both polymerases iota and eta. The absence of both polymerases did not affect production of IgG1, indicating that these enzymes are not involved in switch recombination. Poli(-/-F6) mice had the same types of nucleotide substitutions in variable genes as their C57BL/6 counterparts, and mice doubly deficient for polymerases iota and eta had the same mutational spectrum as Polh-/- mice. Thus, polymerase iota did not contribute to the mutational spectra, even in the absence of polymerase eta.

Animals↗

Behavioural studies of MHC-congenic mice.

Behavioural studies of MHC-congenic mice and rats have focused primarily on mate choice and the ability to discriminate between strains by their urine odours, but these strains may differ in other behaviours, such as activity and ultrasonic vocalizations. Ivanyi (1978, Proc. Roy. Soc. Lord. 202, 117-158) has reviewed the physiological differences associated with the MHC, many of which could influence behaviour. We have started a systematic study of behavioural development and adult behaviour in MHC-congenic mice. A developmental test battery (growth, rate, locomotion, grooming, eye opening, ultrasonic vocalizations, etc.) was used to examine differences between C57BL/6J vs. B6-H-2bml and C57BL/10SnJ vs. B10.BR/sgSnJ mice. A test battery of spontaneous behaviours (activity, exploration, ultrasonic vocalizations, etc.) was used to examine behavioural differences between adult C57BL/6J vs. B6-H-2bml; and C57BL/10SnJ vs. B10.BR/sgSnJ mice. Differences in development and in adult behaviours between these MHC-congenic strains is discussed in relation to possible neural, endocrine and immune system differences. Future studies will compare MHC-congenic mice on levels of anxiety, sociosexual behaviour and on learning paradigms.

Animals↗

Establishment of Bcgr congenic mice and their susceptibility/resistance to mycobacterial infection.

Bcg congenic mice were developed by using C57BL/6 and DBA/2 strains of mice as progenitors. They were obtained by introgressively backcrossing the Bcgr marker of DBA/2 onto C57BL/6. After twenty successive backcrossings, the heterozygous resistant mice were mated with each other to obtain homozygous mice as the Bcgr congenic mice. The results of immunogenic and genetic markers coupled with those of an mixed lymphocyte reaction, all confirmed that the newly developed mice were highly congenic. These congenic mice were found to be resistant to in vivo infections by Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium bovis BCG.

Animals↗

Analyses of acute graft-versus-host-like reaction in [MRL/lpr----MRL/+] chimeric mice using MRL/lpr-Thy-1. 1 congenic mice.

When MRL/Mp(-)+/+(MRL/+) mice are lethally irradiated and then reconstituted with MRL/Mp-lpr/lpr (MRL/lpr) bone marrow and/or spleen cells, these MRL/+ mice develop "lpr-GVHD" which is similar to acute graft-versus-host disease (GVHD). Using a Thy-1 congenic strain of MRL/lpr mice (MRL/lpr-Thy-1.1), we analyzed T cell subpopulations in the thymus and spleen of MRL/+ mice suffering from lpr-GVHD. lpr-GVHD was induced in MRL/+ mice by transplantation of bone marrow cells (BMC) from MRL/lpr-Thy-1.1 mice; severe lymphocyte depletion associated with fibrosis was observed in the spleens after 7 weeks of bone marrow transplantation (BMT). Thymocytes of the host MRL/+ thymus were replaced with donor-derived cells from the early stage of lpr-GVHD, whereas in the spleen, a small number of host T cells (Thy-1.2+) (4-5%) were retained until the late stage of lpr-GVHD. Donor-type (Thy-1.1+) T cell subsets were not different from those of nontreated MRL/+ mice in the thymus, whereas in the spleen. CD8+ T cells (Thy-1.1+) reached a peak at 5 weeks after BMT, and CD4+ T cells (Thy-1.1+), a peak at 6 weeks. The elimination of T cells from MRL/lpr BMC had no evident effect on the prevention of lpr-GVHD. T cell subpopulations showed a similar pattern to GVHD elicited by MHC differences. Analyses of autoreactive T cells expressing V beta 5 or V beta 11 revealed that autoreactive T cells were deleted from the peripheral lymph nodes. Interestingly, the levels of IgG anti-ssDNA antibodies markedly increased, and both IgM and IgG rheumatoid factors slightly increased 5 to 7 weeks after BMT. These findings are discussed in relation to not only GVHD elicited by MHC differences but also autoimmune diseases.

Animals↗

Delineation of two defects responsible for T-cell hyporesponsiveness to concanavalin A in MRL congenic mice.

MRL-lpr mice and their congenic counterparts MRL-+ spontaneously develop an autoimmune disease that resembles systemic lupus erythematosus in humans. The two strains, although congenic, differ by a considerable number of disease parameters, reflecting the expression of the lpr autosomal recessive gene. One paradox that has developed out of the work utilizing the congenic mice is that the gene responsible for lymphoproliferation also appears to be responsible for the inability of T cells to respond to proliferative signals in vitro. In this paper we investigated a possible lpr gene-encoded macrophage defect in these mice. It was found, however, that both the MRL-+ and MRL-lpr mice failed to divide in response to Con A, the lack of division correlating with an inability to secrete the growth promoter interleukin-2. In MRL-+ mice and young MRL-lpr mice this non-responsiveness was corrected by the addition of normal CBA PEC. The defect could not be explained by a failure of MRL-+ or MRL-lpr peritoneal exudate cells to quantitatively or qualitatively provide a source of interleukin-1 to Con A-activated T cells or by the possibility that the peritoneal exudate cells were blocked in their function by the presence of sera-derived autoantibodies and/or immune complexes on their membranes. We postulate that the inability of T cells to proliferate in MRL congenic mice can be explained by two defects: the failure of antigen-presenting cells in MRL-+ and MRL-lpr to provide the necessary signals to immunocompetent T cells, this defect not being associated with the lpr gene, and the lpr gene controlled outgrowth of a unique T-cell population that cannot respond in our assay system.

Animals↗