Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “coding variants”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,495 records · Page 83Linked to original sources
PubMed2002

Cloning of CYP2J2 gene and identification of functional polymorphisms.

CYP2J2 is abundant in cardiovascular tissue and active in the metabolism of arachidonic acid to eicosanoids that possess potent anti-inflammatory, vasodilatory, and fibrinolytic properties. We cloned and sequenced the entire CYP2J2 gene (approximately 40.3 kb), which contains nine exons and eight introns. We then sequenced the CYP2J2 exons and intron-exon boundaries in 72 healthy persons representing African, Asian, and European/white populations as part of the National Institutes of Health/National Institute of Environmental Health Sciences Environmental Genome Single Nucleotide Polymorphism Program. A variety of polymorphisms were found, four of which resulted in coding changes (Arg158Cys, Ile192Asn, Asp342Asn, and Asn404Tyr). A fifth variant (Thr143Ala) was identified by screening a human heart cDNA library. All five variant cDNAs of CYP2J2 were generated by site-directed mutagenesis and expressed in Sf9 insect cells by using a baculovirus system. The recombinant wild-type and variant CYP2J2 proteins immunoreacted with peptide-based antibodies to CYP2J2 and displayed typical cytochrome P450 (P450) CO-difference spectra; however, the Asn404Tyr and Ile192Asn variants also had prominent spectral peaks at 420 nm. The ability of these variants to metabolize arachidonic acid and linoleic acid was compared with that of wild-type CYP2J2. Three variants (Asn404Tyr, Arg158Cys, and Thr143Ala) showed significantly reduced metabolism of both arachidonic acid and linoleic acid. The Ile192Asn variant showed significantly reduced activity toward arachidonic acid only. The Asp342Asn variant showed similar metabolism to wild-type CYP2J2 for both endogenous substrates. Based on these data, we conclude that allelic variants of the human CYP2J2 gene exist and that some of these variants result in a P450 protein that has reduced catalytic function. Insofar as CYP2J2 products have effects in the cardiovascular system, we speculate that these variants may be functionally relevant.

Alleles↗
PubMed1992

In vitro selection of variants of human immunodeficiency virus type 1 resistant to 3'-azido-3'-deoxythymidine and 2',3'-dideoxyinosine.

Drug-resistant variants of human immunodeficiency virus type 1 (HIV-1) have been isolated by in vitro selection. MT-4 cells were infected with either a laboratory strain (HIV-IIIB) or a clinical isolate (no. 187) of HIV-1 and maintained in medium containing subeffective concentrations of the drugs 3'-azido-3'-deoxythymidine (AZT) and 2',3'-dideoxyinosine (ddI). By gradually increasing the drug concentration in the culture medium during propagation of the virus on fresh MT-4 cells, we were able to isolate variants of HIV-IIIB and clinical isolate 187 which showed up to 100-fold increases in resistance to the drugs. The drug resistance phenotypes remained stable after propagation of the variants in the absence of drug pressure for over 2 months. However, variants resistant to one drug showed little or no cross-resistance to the other, suggesting that the genetic bases for resistance to the compounds differed. Genotypic analysis of these nucleoside-resistant variants by polymerase chain reaction (PCR) with primer pairs previously shown to correspond to mutations responsible for resistance to AZT was also carried out. A heterogeneity of genotypes was observed, with known mutations at pol codons 70 and 215 occurring in most of the AZT-resistant variants generated from either HIV-IIIB or clinical strain 187. However, mutations in codons 67 and 219 were less frequently detected, and none of these changes were observed in each of four variants resistant to ddI. Cloning and sequencing studies of the reverse transcriptase coding region of two of the isolates were also performed and confirmed the PCR data that had been obtained. In addition to previously described mutation sites responsible for resistance to AZT, an HIV-IIIB-resistant variant was shown to be mutated at positions 108 (Val----Ala) and 135 (Ile----Thr), while a resistant variant of strain 187 was mutated at positions 50 (Ile----Val) and 135 (Ile----Val).

Base Sequence↗
PubMed2006

SOD1: a candidate gene for keratoconus.

PURPOSE: To screen superoxide dismutase 1 (SOD1) on chromosome 21 as a possible candidate gene for familial keratoconus (KC). METHODS: Total genomic DNA was extracted from the blood of 15 different KC families and 156 unaffected subjects. All five exons of the SOD1 gene were sequenced. For a rapid screening test, DNA was amplified by polymerase chain reaction (PCR), digested with HpyCH4 III or analyzed by radioactively end-labeled exon PCR. RNA was extracted from leukocytes and reverse transcribed to cDNA, and the PCR was amplified for splice variants. Some samples were cloned and sequenced. RESULTS: A heterozygous genomic 7-base deletion in intron 2 of the SOD1 gene was identified in two KC families (pedigrees 1 and 6). The deletion segregated within pedigree 1 and was absent in 312 chromosomes from normal individuals. RNA from the proband of pedigree 1 showed that in addition to the wild-type transcript, two other transcripts were expressed for the CuZn SOD (SOD1) gene: lacking entire exon 2 (LE2) and lacking entire exon 2 and entire exon 3 (LE2E3). CONCLUSIONS: A unique genomic deletion within intron 2 close to the 5' splice junction of the SOD1 gene was identified in three patients with KC. Moreover, mRNA from one affected individual also had two transcript splice variants (LE2 and LE2E3) that others have shown to code for proteins lacking the active site of the SOD1 enzyme. Further studies should be conducted to determine whether a causal relationship exists between these two events that may increase oxidative stress and be associated with KC.

Adult↗
PubMed2006

Discordance between N-acetyltransferase 2 phenotype and genotype in a population of Hmong subjects.

Polymorphisms of N-acetyltransferase 2 (NAT2) acetylation may influence drug toxicities and efficacy and are associated with a differential susceptibility to select cancers. Acetylation phenotype may have clinical implications. The purposes of this study were to determine the genetic basis of an apparent predominance of slow acetylation phenotype and to assess concordance with genotype in a population of Hmong residing in Minnesota. Urine and DNA obtained from unrelated Hmong 18 to 65 years of age were used to determine phenotype from caffeine metabolites, whereas direct nucleotide sequencing of the NAT2 coding region, followed by cloning, identified all known allelic variants. From 61 subjects (27 men, 30 +/- 11 years), analysis of 50 urine-DNA pairs identified 46 (92%) slow acetylators and 4 (8%) rapid acetylators by phenotype. Genotypic analysis inferred 5 (10%) slow acetylators and 45 (90%) rapid acetylators. There is 86% discordance between phenotype and genotype. A predominance of NAT2 slow acetylation phenotype in the Hmong is confirmed, and a significant discordance between NAT2 phenotype and genotype is identified. In this population, slow acetylation phenotype determined by a metabolic probe would not have been predicted by genotype alone. Environmental, genetic, or phenotypic anomalies that may contribute to this discordance should be considered and evaluated in future studies within this unique population.

Acetylation↗
PubMed2006

No direct effect of the -521 C/T polymorphism in the human dopamine D4 receptor gene promoter on transcriptional activity.

BACKGROUND: The human dopamine D4 receptor (DRD4) gene has been studied extensively as a candidate gene for certain psychological traits and several behavioural and psychiatric disorders. Both the 5' regulatory region and the coding sequence contain a number of polymorphisms. The promoter variants have received particular attention in the past few years due to their possible role in the regulation of gene transcription. Previously, the -521C/T SNP was shown to influence promoter activity. The aim of this study is to perform an in-depth analysis of this effect in the context of various neural cell lines. RESULTS: Endogenous mRNA expression of the DRD4 gene was demonstrated in two neuroblastoma (SK-N-F1, IMR32) and one retinoblastoma cell line (Y79) by RT-PCR. In addition, very low DRD4 mRNA levels were also detected in HeLa cells. The transcriptional activity of a series of 5' promoter deletion mutants was determined by transient transfection of luciferase reporter constructs. The activity profile of these promoter fragments was similar in each of the cell lines tested. The highest luciferase reporter activity was obtained with a construct containing promoter sequences between nucleotides -668 to -389, while a putative silencer region was localised spanning from nucleotide -1571 to -800. Surprisingly, the -521 C/T polymorphism had no significant effect on transcriptional activity of the reporter construct with the highest activity (-668 to -389) in any of the three cell lines tested. CONCLUSION: Our results do not confirm previous data assigning different transcriptional activities to the -521 C/T alleles of the human DRD4 promoter. Furthermore, these findings highlight the need for further characterization of the 5' regulatory region of the DRD4 gene and identification of additional functional promoter polymorphic sites, especially in the context of haplotype.

Cell Line, Tumor↗
PubMed1995

Soviet policy toward male homosexuality: its origins and historical roots.

Sodomy was a crime under tsarist criminal law. Having abrogated the tsarist legal codes in the name of socialist justice, the new Soviet regime did not at first impose criminal sanctions on sodomy. It was only in 1934, after Stalin had consolidated power, that an anti-sodomy statute was added to the Soviet criminal code. Although Russian radicals had never been friendly to variant sexual practices, which they viewed as the product of capitalist decadence, Soviet sexologists in the 1920s participated in the international movement for sexual reform and criminologists deplored the use of penal sanctions to censor private sexual conduct. The 1934 return to legal prosecution represented the recovery of two traditions: the radicals' disregard for issues of sexual freedom and tsarist legal custom. It was not, however, a clear reversal of the seemingly enlightened legal practice of the 1920s. This essay examines the trial of a group of homosexual men and the investigation of a lesbian couple, both from 1922, which show that Soviet courts tried to repress sexual variation even when homosexuality was not a crime. These cases and the status of homosexuality in general reflect on the murky status of the law and on the ambiguities of Soviet politics in the early years of the new regime.

Communism↗
PubMed2004

A novel tetrameric short tandem repeat located in the 3' flanking region of the human ABO-secretor gene (FUT2) and association between FUT2 and FUT2/01 loci.

We found a novel polymorphic short tandem repeat (FUT2/01), 3.8 kb downstream of the coding region of FUT2. Seventeen length and 33 sequence variants were identified in 300 individuals representing three major human populations. Africans (Xhosa) and Europeans were characterized by high microvariation, and Japanese were characterized by a simple repeat structure. All exhibited high haplotype diversity.

ABO Blood-Group System↗
PubMed2006

Functional implication of an Arg307Gly substitution in corticosteroid-binding globulin, a candidate gene for a quantitative trait locus associated with cortisol variability and obesity in pig.

We previously reported that corticosteroid-binding globulin gene (Cbg) may be the causal gene of a quantitative trait locus associated with cortisol levels, fat deposition, and muscle content in a pig intercross. Sequence analysis of parental animals allowed us to identify four amino-acid substitutions. Here we have examined if any of these single amino acid substitutions could be responsible for the difference in CBG binding and affinity for cortisol between the parental breeds, using in vitro assays of Cbg variants after transfection of mammalian cells. Additionally, the Cbg coding region was analyzed in samples from a synthetic pig line to study association between polymorphism and CBG biochemical properties, carcass composition, and meat quality. Both in vitro transfection assays and the association studies suggest a role of the Arg307Gly mutation in increasing CBG capacity (by >70%) and decreasing CBG affinity for cortisol (by 30%). The Ile265Val substitution may also have an effect on decreasing CBG affinity for cortisol by 25%. The mutations Ser15Ile and Thr257Met do not seem to have an effect on CBG parameters. The Arg307Gly substitution was the only mutation associated with a parameter of meat quality and no mutation was linked to carcass composition.

Amino Acid Substitution↗
PubMed1999

Mutations in von Willebrand factor multimerization domains are not a common cause of classical type 1 von Willebrand disease.

Type 1 von Willebrand disease (vWD) is an autosomal dominant bleeding disorder of variable penetrance. It is characterised by a mild to moderate bleeding tendency and a quantitative deficiency of von Willebrand factor (vWF) with the full range of vWF multimers. Few mutations have been described which account for the mode of inheritance in dominant vWD type 1. We screened the vWF multimerization domains (regions D1-D3 of the vWF gene) of 12 unrelated patients with dominant vWD type 1 to investigate the hypothesis that multimerization of vWF sub-units may be inhibited or reduced by a "dominant negative" mechanism. Platelet-derived RNA was reverse transcribed and the resulting vWF cDNA amplified by the polymerase chain reaction (PCR) in a series of overlapping fragments. These were subjected to a combination of single-strand conformation polymorphism (SSCP) and heteroduplex analysis. This approach identified mobility shifts on acrylamide gels that represented 12 distinct SSCP and/or heteroduplex patterns in our patient group. DNA sequencing of the region encompassing each mobility shift showed these variants to represent previously described polymorphisms within the vWF coding sequence. Examination in all 12 patients for the previously described G3389T and T3445C mutations proved negative. The molecular pathology of classical type 1 vWD remains enigmatic, mutations having been identified in only a small minority of patients. A common mechanism underlying this disease state has still to be elucidated.

Amino Acid Substitution↗
PubMedDate not supplied

Soluble interleukin-6 receptor in plasma and in lymphocyte culture supernatants of healthy individuals and patients with systemic lupus erythematosus and rheumatoid arthritis.

The soluble IL-6 receptor (sIL-6R) occurring in various body fluids of healthy persons and patients with various diseases is an agonist since its complex with IL-6 binds to gp130 making IL-6 receptor negative cells responsive for IL-6. The generation as well as the functional role of soluble IL-6 receptor is poorly understood. We measured the sIL-6R levels by ELISA sandwich technology in sera and in supernatants of lymphocyte cultures without and after incubations with dexamethasone. Our results indicate, that the sIL-6R levels in sera of patients with inactive systemic lupus erythematosus (SLE) and active rheumatoid arthritis (RA) were higher than those of the control group, active SLE and inactive RA. In vitro dexamethasone treatment stimulated generation of sIL-6R in both healthy persons and in active SLE, however it strongly suppressed sIL-6R in both RA groups. At mRNA level, we found that in SLE both the mRNA coding the cell-bound and an alternatively spliced variant corresponding to soluble IL-6R transcript increases, however the strong decrease of sIL6R protein in RA was not found at mRNA level.

Adult↗
PubMed2004

CFR-1 receptor as target for tumor-specific apoptosis induced by the natural human monoclonal antibody PAM-1.

The human monoclonal antibody PAM-1 was isolated from a patient with stomach cancer. The germ-line coded IgM antibody identifies a recently described 130 kDa variant of CFR-1 (cysteine-rich fibroblast growth factor receptor 1). This CFR-1/PAM-1 receptor is post-transcriptionally modified and over-expressed on human epithelial tumors and carcinoma pre-cancer lesions such as H. pylori induced gastritis, intestinal metaplasia and dysplasia of the stomach, ulcerative colitis-related dysplasia and adenomas of the colon, Barrett metaplasia and dysplasia of the esophagus, squamous cell metaplasia and dysplasia of the lung and cervical intraepithelial neoplasia. Furthermore, the expression of CFR-1/PAM-1 correlates with the proliferation rate and increases with the grade of malignancy. This study demonstrates that the human monoclonal antibody PAM-1 inhibits cell growth and induces apoptosis, in vitro and in vivo. Both, the unique tumor-specific expression of the CFR-1/PAM-1 receptor and the growth inhibitory effect of the PAM-1 antibody makes this combination a good diagnostic and therapeutic tool for all kinds of epithelial cancers and precursor lesions.

Adenocarcinoma↗
PubMed2002

Expression of the mouse FGF-1 and FGF-1.A mRNAs during embryonic development and in the aging heart.

The mouse Fgf-1 gene contains at least four upstream promoters that are alternatively spliced to the first protein coding exon, giving rise to different Fgf-1 mRNA variants (1.A, 1.B, 1.C, and 1.G), each expressed in a tissue specific manner. Only the Fgf-1.A promoter contains TATA and CAAT consensus sequences, and its corresponding mRNA is mainly expressed in the mouse heart. In situ hybridization with an Fgf-1.A-specific cRNA probe showed the 1.A message to be very low in embryonic heart, tongue, spinal cord and smooth muscle of the small intestine. Moderate 1.A mRNA levels were revealed in head mesenchyme, paraxial mesoderm, in the embryonic inferior cunniculus, hyppocampus, and thymus. These results suggest a limited role of the Fgf-1.A mRNA variant during development.

Aging↗
PubMed1991

Generation of the truncated form of the nerve growth factor receptor by rat Schwann cells. Evidence for post-translational processing.

These studies were initiated to determine whether the soluble, truncated form of the nerve growth factor (NGF) receptor arises from post-translational processing of the intact, membrane-bound receptor or from an alternatively spliced mRNA. Pulse-chase analysis of cultured primary rat Schwann cells coupled with immunoprecipitations using antibodies to the intracellular and extracellular domains of the receptor were used to monitor receptor production. Three forms of the NGF receptor (80, 83, and 85 kDa) displaying a precursor product relationship were detected over the 2-h chase period; only the 85-kDa species was detected on the cell surface. Truncated receptors (50 and 52 kDa) were detected in conditioned media 5 h after cell labeling but were never observed intracellularly. Polymerase chain reaction and RNase protection analyses of NGF receptor mRNA targeted toward the coding region for the transmembrane domain detected no splice variants that could generate truncated receptor, and media conditioned by fibroblasts transfected with rat receptor cDNA, in which splicing cannot occur, nonetheless contained the truncated receptor protein. Taken together, these results suggest that the truncated NGF receptor does not arise as a distinct translation product but rather from a post-translational modification of the intact, surface-bound form of the protein.

Amino Acid Sequence↗
PubMed1991

[Polydactyly of the hands. Recommendation for expanded classification].

The few anatomical findings summarized in the literature have now been expanded by our own anatomical dissections on four hands of still-born infants with postaxial polydactyly, and by intra-operative microsurgical investigations of 25 polydactylous hands. New experimentally-based knowledge of embryology helps interpret the morphogenesis and specific anatomy of polydactyly. It can be postulated that both the location and definite form of polydactyly are a function of the location and extent of initial excessive cell proliferation and disturbance of cell necrosis in the hand blastema. The conclusive discussion of special findings regarding anatomical structures shows regular pattern formations which lend themselves to a broader classification. The classification of malformations of the hand by Temtamy and McKusick was used as a framework for the classification of polydactyly, whether it was existing as an isolated form or as part of a syndrome. The osteological types I to VI found by Wassel in thumb duplication are confirmed by our anatomical findings. Special coding of anatomical findings enabled us to identify four variants and three forms, depending on the development of the digital palmar arteries and nerves. For the triphalangeal pre-axial fingers and the post-axial fifth finger, the five osteological types described by Müller and those described by Duhamel are increased to ten. Comparison with our anatomical findings shows four variants of these osteological types. For post-axial polydactyly, types XI through XIV, existing in three variants, have been defined.

Fingers↗
PubMed1993

Expression of endogenous NMDAR1 transcripts without receptor protein suggests post-transcriptional control in PC12 cells.

Expression of RNA for the NMDAR1 subunit of the N-methyl-D-aspartate receptor was detected by Northern hybridization in both nerve growth factor-differentiated and undifferentiated rat pheochromocytoma (PC12) cells. The NMDA receptor type 1 (NMDAR1) message in PC12 cells was similar in size to that expressed in hippocampal neurons. PC12 cell cDNAs that were amplified by polymerase chain reaction with primers flanking the coding region of NMDAR1 corresponded to the NMDAR1 splice variant NMDA receptor type 1 isoform C (NMDAR1C). Using calcium imaging or patch-clamp recording, no functional NMDA-gated ion channels were found in PC12 cells. A monoclonal antibody against NMDAR1 was developed in order to investigate whether or not NMDAR1 protein was present in PC12 cells. Only trace amounts of NMDAR1 protein were found in native PC12 cells. However, expression of NMDAR1 protein was detected in PC12 cells that were transfected with an expression vector containing an NMDAR1C clone under control of a cytomegalovirus promoter. These findings suggest that the expression of NMDAR1 protein in PC12 cells may be controlled by post-transcriptional mechanisms. The PC12 cell line may serve as a model system for the study of the transcriptional, post-transcriptional, and translational regulation of NMDAR1. Furthermore, the presence of NMDAR1 RNA in a particular cell type may not necessarily indicate expression of NMDAR1 protein.

Alternative Splicing↗
PubMed1996

Expression of two alternatively spliced forms of the 5' untranslated region of the GM-CSF receptor alpha chain mRNA.

The granulocyte-macrophage colony-stimulating factor receptor (GM-CSFR) is composed of at least two chains (alpha and beta). The alpha chain binds GM-CSF specifically with low affinity, and the binding is converted to high affinity when the alpha chain is associated with the beta chain. To date, there are at least six isoforms described for the GM-CSFR alpha, all involving alternative splicing at the 3' end, which alters the coding region and hence the protein produced. To detect variants at the 5' end of the GM-CSFR alpha mRNA, RNAse protection and reverse transcriptase polymerase chain reaction (RT-PCR) assays were performed using a probe spanning nucleotides 102-392 and pairs of primers covering exons 1-4. in addition to the expected full-length transcript, two mRNAs were detected, one containing a deletion of 24 nucleotides by alternative splicing at the 3' end of exon 2 (exon 2b-deleted isoform) and another in which exon 2 was completely deleted (exon 2-deleted isoform). Together, the isoforms were more highly expressed form). Together, the isoforms were more highly expressed than the full-length sequence (TF-1 cells: full-length 36 +/- 2.8% vs. exon 2-deleted isoforms 64 +/- 5.5%). These isoforms were detected in primary hematopoietic cells, blasts from patients with acute myeloid leukemia (AML), and malignant cell lines and the relative mRNA expression for the isoforms, was always similar to that of TF-1 cells. As sequences in the 5'untranslated region can be involved in the modulation of translational efficiency, translation of constructs constructs corresponding to these exon 2 deleted isoforms was assessed using an in vitro reticulocyte lysate system. Deletion of exon 2 resulted in significantly lower in vitro translation of the receptor protein relative to the full-length sequence (53, 56, and 76% in three separate batches of reticulocytes), while deletion of exon 2b resulted in higher translation of the sequence (164, 128, and 305%; p = 0.01). These data suggest a mechanism by which expression of the GM-CSFR alpha protein may be regulated by alternatively spliced transcripts with different translational efficiencies.

Acute Disease↗
PubMed1996

Influence of the degree of renal dysfunction on the pharmacokinetic properties of the novel recombinant plasminogen activator reteplase in rats.

Reteplase (drug code: BM 06.022) is an unglycosylated recombinant plasminogen activator variant derived from human tissue-type plasminogen activator. The main metabolic organs of reteplase are the kidneys, liver, and blood, whereas human tissue-type plasminogen activator is predominantly cleared by the liver. Recent studies showed that reteplase plasma concentrations were significantly increased in severe acute renal failure. The purpose of the present study was to evaluate whether the degree of renal failure influences the pharmacokinetic properties of reteplase. Subacute renal failure in rats was induced by bilateral 1-hr clamping of the renal arteries and recovery for 3 or 6 days. Acute renal failure was induced by bilateral surgical nephrectomy. Renal function was assessed by inulin clearance. The plasma concentration of functionally active reteplase was measured by an indirect spectrophotometric assay. Reteplase was administered as a double-bolus intravenous injection of 140 + 140 kU/kg, 30 min apart. In comparison with sham surgery, 1-hr clamping plus recovery for 6 days had the least effect on inulin clearance, followed by clamping and recovery for 3 days and bilateral nephrectomy (20.2 +/- 1.8 vs. 13.0 +/- 1.3, 8.3 +/- 0.8, and 3.1 +/- 0.2 ml center dot min-1 center dot kg-1, p < 0.01). Total plasma clearance of reteplase was significantly reduced, compared with sham surgery after 1-hr clamping plus 3-day recovery and bilateral nephrectomy (3.65 +/- 0.26 vs. 2.6 +/- 0.23 and 2.18 +/- 0.14 ml center dot min-1 center dot kg-1, p < 0.05 and p < 0.01, respectively), but not after 1-hr clamping plus 6-day recovery (3.33 +/- 0.34 ml center dot min-1 center dot kg-1, NS vs. sham surgery). There was a significant (p < 0.0001) linear correlation (r = 0.713) between the decrease of inulin clearance and the decrease of reteplase clearance. These data indicate that slight impairment of renal function does not significantly influence pharmacokinetic properties of reteplase, whereas severe renal dysfunction does.

Acute Kidney Injury↗
PubMed1997

Structural organization and expression of the gene for the mouse GM2 activator protein.

The GM2 activator protein is an essential component for the degradation of GM2 ganglioside by hexosaminidase A in vivo. Mutations in the human gene coding for the GM2 activator protein cause the AB variant of GM2-gangliosidosis, a condition that is clinically indistinguishable from Tay-Sachs disease. To understand better factors affecting the expression of the GM2 activator protein gene (Gm2a) in mouse tissues, we have determined its exon-intron organization and analyzed its promoter region. Gm2a is about 14 kb, has four exons, and the 5' flanking region contains a CAAT box, Sp1 binding sites, AP-1, AP-2 sites, and a pair of IRE sites. A 1.2-kb fragment upstream from the initiation codon was shown to have promoter activity in NIH 3T3 cells. Similarities between the elements present in Gm2a and Hexa promoters might in part explain their similar expression patterns in mouse tissues. The different levels of GM2 activator protein mRNA in liver, kidney, brain, and testis are not owing to the use of different transcription start sites, because a single start site was found 50 bp upstream from the initiation codon in each these tissues. Northern blot analysis demonstrated variation in the GM2 activator protein mRNA expression during mouse development. Gm2a was mapped to Chromosome (Chr) 11, where it co-segregated with Csfgm.

3T3 Cells↗