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PubMed2024

Stemness related lncRNAs signature for the prognosis and tumor immune microenvironment of ccRCC patients.

Long non-coding RNAs (lncRNAs) and cancer stem cells (CSCs) are crucial for the growth, migration, recurrence, and medication resistance of tumors. However, the impact of lncRNAs related to stemness on the outcome and tumor immune microenvironment (TIME) in clear cell renal cell carcinoma (ccRCC) is still unclear. In this study, we aimed to predict the outcome and TIME of ccRCC by constructing a stem related lncRNAs (SRlncRNAs) signature. We firstly downloaded ccRCC patients' clinical data and RNA sequencing data from UCSC and TCGA databases, and abtained the differentially expressed lncRNAs highly correlated with stem index in ccRCC through gene expression differential analysis and Pearson correlation analysis. Then, we selected suitable SRlncRNAs for constructing a prognostic signature of ccRCC patients by LASSO Cox regression. Further, we used nomogram and Kaplan Meier curves to evaluate the SRlncRNA signature for the prognose in ccRCC. At last, we used ssGSEA and GSVA to evaluate the correlation between the SRlncRNAs signature and TIME in ccRCC. Finally, We obtained a signtaure based on six SRlncRNAs, which are correlated with TIME and can effectively predict the ccRCC patients' prognosis. The SRlncRNAs signature may be a noval prognostic indicator in ccRCC.

Humans↗
PubMed1994

Increase in the relative fitness of a plant virus RNA associated with its recombinant nature.

A recombination event at the 3' end of RNA 3 in a pseudorecombinant virus (C1C2T3) having RNAs 1 and 2 from TrK7-cucumber mosaic virus (CMV) and RNA 3 from P-tomato aspermy virus (TAV) was detected by ribonuclease protection assay (RPA). Sequence analysis of the 3' end of RNA 3 of C1C2T3 and of its parental CMV and TAV strains showed that RNA 3 of C1C2T3 had a hybrid nature in which most of the 3' noncoding region (3' ncr), including the whole 3' terminal tRNA-like structure, was derived from CMV RNA 2 by recombination. Recombination may have occurred in two steps. The first one would have caused the duplication of a large region 5' to the 3' end tRNA-like structure, derived from TAV and from CMV. The second one would have eliminated the TAV-derived sequences in this duplicated region. Competition experiments in tobacco plants showed that in a context of RNA 1 + 2 from CMV, RNA 3 from TAV is outcompleted by RNA 3 of CMV, but the recombinant TAV RNA 3 with the 3' end of CMV outcompetes both TAV and CMV RNA 3. This shows an increase in relative fitness associated with the recombinant nature of RNA 3. Our results document the potential importance of RNA-RNA recombination in the determination of the genetic structure of RNA viral populations.

Base Sequence↗
PubMed2000

Identification of RpoS (sigma(S))-regulated genes in Salmonella enterica serovar typhimurium.

The rpoS gene encodes the alternative sigma factor sigma(S) (RpoS) and is required for survival of bacteria under starvation and stress conditions. It is also essential for Salmonella virulence in mice. Most work on the RpoS regulon has been in the closely related enterobacterial species Escherichia coli. To characterize the RpoS regulon in Salmonella, we isolated 38 unique RpoS-activated lacZ gene fusions from a bank of Salmonella enterica serovar Typhimurium mutants harboring random Tn5B21 mutations. Dependence on RpoS varied from 3-fold to over 95-fold, and all gene fusions isolated were regulated by growth phase. The identities of 21 RpoS-dependent fusions were determined by DNA sequence analysis. Seven of the fusions mapped to DNA regions in Salmonella serovar Typhimurium that do not match any known E. coli sequence, suggesting that the composition of the RpoS regulon differs markedly in the two species. The other 14 fusions mapped to 13 DNA regions very similar to E. coli sequences. None of the insertion mutations in DNA regions common to both species appeared to affect Salmonella virulence in BALB/c mice. Of these, only three (otsA, katE, and poxB) are located in known members of the RpoS regulon. Ten insertions mapped in nine open reading frames of unknown function (yciF, yehY, yhjY, yncC, yjgB, yahO, ygaU, ycgB, and yeaG) appear to be novel members of the RpoS regulon. One insertion, that in mutant C52::H87, was in the noncoding region upstream from ogt, encoding a O(6)-methylguanine DNA methyltransferase involved in repairing alkylation damage in DNA. The ogt coding sequence is very similar to the E. coli homolog, but the ogt 5' flanking regions were found to be markedly different in the two species, suggesting genetic rearrangements. Using primer extension assays, a specific ogt mRNA start site was detected in RNAs of the Salmonella serovar Typhimurium wild-type strains C52 and SL1344 but not in RNAs of the mutant strains C52K (rpoS), SL1344K (rpoS), and C52::H87. In mutant C52::H87, Tn5B21 is inserted at the ogt mRNA start site, with lacZ presumably transcribed from the identified RpoS-regulated promoter. These results indicate that ogt gene expression in Salmonella is regulated by RpoS in stationary phase of growth in rich medium, a finding that suggests a novel role for RpoS in DNA repair functions.

Animals↗
PubMed1993

Comparative analysis of the rotavirus NS53 gene: conservation of basic and cysteine-rich regions in the protein and possible stem-loop structures in the RNA.

NS53, the product of rotavirus gene 5, is an RNA-binding protein that contains a cysteine-rich region and is a component of early replication intermediates. To gain information about the structure of NS53 and its RNA, we determined the nucleotide sequence of gene 5 for the human viruses Wa (serotype 1) and DS1 (2) and the simian virus SA11 (3) (Patton strain) and compared them and their deduced amino acid sequences to those reported for the bovine viruses UK (6) and RF (6), SA11 (3) (Both strain), the human virus Rohivg803, and the group C porcine virus PRV. The results showed that gene 5 for human, simian, and bovine strains have lengths of 1564-1567, 1611, and 1579-1581 nucleotides (nt) and encode proteins of 486, 495, and 491 amino acids, respectively. Comparison of the protein sequences for NS53 among different serotypes showed that they are extremely divergent with many sharing amino acid homologies of only 36-38%. Even NS53 from viruses isolated from the same species possessed relatively poor homology, e.g., DS1 versus Wa was 68%. The first 150 amino acids of NS53 exhibited a greater degree of conservation than the rest of the protein. Near the amino terminus, NS53 contains three basic regions and a cysteine-rich domain, suggesting that this area is responsible for the RNA-binding activity of the protein. Present in the cysteine-rich domain of all group A and C viruses was the motif C-X2-C-X8-C-X2-C-X3-H-X-C-X2-C-X5-C. Although this motif may form one or two zinc fingers, the fact that it is highly conserved indicates that it plays a critical role in the function of protein. Comparison of the nucleotide sequences for gene 5 showed that the entire 5'-noncoding region and the first 24 nt of the NS53 ORF are conserved. RNA-folding predictions suggest that this region of the NS53 mRNA can interact with itself, producing a stem-loop structure similar to that found near the 5'-terminus of the NS35 mRNA. Thus, such structures may be common to all rotavirus mRNAs, perhaps functioning as signals for packaging of RNAs into replication intermediates or regulating mRNA translation.

Amino Acid Sequence↗
PubMed1986

A chimeric plasmid from cDNA clones of poliovirus and coxsackievirus produces a recombinant virus that is temperature-sensitive.

We have inserted a 405-nucleotide fragment from the 5' noncoding region of the coxsackievirus B3 genome into an infectious cDNA copy of the poliovirus RNA genome. Transfection of plasmid DNA containing this hybrid genome construct into cultured monkey cells produced infectious virus. Recombinant virus stocks displayed a temperature-sensitive phenotype for growth at 37 degrees C. We found that there is a dramatic reduction in the level of viral proteins and viral RNAs in HeLa cells infected with the recombinant at 37 degrees C compared to that obtained at 33.5 degrees C. Thus, insertion of a portion of the coxsackievirus genome into the poliovirus genome produces a temperature-sensitive recombinant virus. That this substitution occurs in a region of the poliovirus genome that, to date, has not been shown to have any coding function suggests that RNA sequences involved in replicase recognition or ribosome binding may contribute to the temperature-sensitive phenotype of the recombinant virus.

Animals↗
PubMed1981

Translational activity and functional stability of human fibroblast beta 1 and beta 2 interferon mRNAs lacking 3'-terminal RNA sequences.

Polyadenylylated mRNA was purified from poly(I).poly(C)- and cycloheximide-superinduced human fibroblast (FS-4) cultures. The mRNA was subjected to electrophoresis through an agarose/CH3HgOH gel, and human fibroblast beta 1 and beta 2 interferon mRNAs were isolated. Each mRNA preparation was phosphorolyzed at 0 degrees C for 20 min by using a molar excess of polynucleotide phosphorylase to produce RNAs lacking poly(A) and then incubated at 37 degrees C for varying lengths of time to allow the phosphorylase to further digest the deadenylylated RNA from the 3' end in a processive and synchronous manner. Removal of the poly(A) (less than or equal to 100 residues) and approximately 100 adjacent residues from human fibroblast beta 1 interferon mRNA (native length, 900 residues, including a 3'-noncoding region of 203 residues) did not alter the translational activity or the functional stability of this mRNA in Xenopus oocytes, whereas deletion of the poly(A) and approximately 200 adjacent residues decreased its translational efficiency. On the other hand, removal of the poly(A) (approximately 200 residues) and approximately 200 adjacent residues from human fibroblast beta 2 interferon mRNA (native length, 1300 residues) did not alter the translational activity or the functional stability of this molecule in oocytes. Thus, neither the poly(A) nor large segments of the 3'-noncoding region (which includes the hexanucleotide A-A-U-A-A-A sequence, at least in the case of beta 1 mRNA) are required for the maintenance of the functional stability of human beta 1 and beta 2 interferon mRNAs in Xenopus oocytes.

Animals↗
PubMed1997

Engineering of homologous recombination hotspots with AU-rich sequences in brome mosaic virus.

Previously, we observed that crossovers sites of RNA recombinants clustered within or close to AU-rich regions during genetic recombination in brome mosaic bromovirus (BMV) (P. D. Nagy and J. J. Bujarski. J. Virol. 70:415-426, 1996). To test whether AU-rich sequences can facilitate homologous recombination, AU-rich sequences were introduced into parental BMV RNAs (RNA2 and RNA3). These insertions created a homologous RNA2-RNA3 recombination hotspot. Two other AU-rich sequences also supported high-frequency homologous recombination if a common sequence with high or average G/C content was present immediately upstream of the AU-rich element. Homologous RNA recombination did not require any additional sequence motifs or RNA structures and was position nonspecific within the 3' noncoding region. These results suggest that nucleotide content (i.e., the presence of common 5' GC-rich or moderately AU-rich and 3' AU-rich regions) is the important factor that determines the sites of homologous recombination. A mechanism that involves replicase switching during synthesis of positive-sense RNA strands is presented to explain the observed results.

Base Sequence↗
PubMed1986

The 3'-nucleotides of flavivirus genomic RNA form a conserved secondary structure.

The terminal noncoding regions of viral RNA genomes are presumed to contain signal sequences and sometimes also secondary structures involved in regulating viral RNA synthesis. Such signals would be expected to be highly conserved among related viruses. In order to identify replication signal features for flaviviruses we have compared the 3'-terminal nucleotide sequences of West Nile virus (WNV), Saint Louis encephalitis (SLE) virus, and yellow fever virus (YFV) genome RNAs. The existence of a stable 3'-terminal secondary structure was previously predicted by a cDNA sequence obtained from YFV genome RNA. We have confirmed the existence of this structure by direct RNA sequencing methods. Even though the size and shape of the 3'-terminal secondary structure is highly conserved, sequence conservation is restricted to the loop regions of the secondary structure and to 27 nucleotides immediately adjacent to the 5' side of the structure. The regions of conserved sequence represent likely signals for viral polymerase recognition and binding. However, the preservation of the configuration of the secondary structure by a means other than sequence conservation indicate that this structure is important for the survival of the virus. A WNV mutant, which replicates progeny genome RNA more efficiently than parental WNV, was found to have a 3'-genomic sequence identical to that of its parent virus. The sequence change conferring the phenotype of this mutant is therefore located in another region of the genome.

Base Sequence↗
PubMed2000

Distinct mRNAs that encode La autoantigen are differentially expressed and contain internal ribosome entry sites.

Analysis by reverse transcription-polymerase chain reaction has suggested the existence of at least two La autoantigen-encoding mRNAs that contain different 5' noncoding regions (NCRs) linked to the same La coding region (Troster, H., Metzger, T. E., Semsei, I., Schwemmle, M., Winterpacht, A., Zabel, B., and Bachmann, M. (1994) J. Exp. Med. 180, 2059-2067). La-encoding transcripts La1 and La1' contain 115- and 483-nucleotide 5' NCRs, respectively. To determine whether the various La transcripts are functional mRNAs, the expression and polysomal association of natural La1 and La1' RNAs were examined. Although La1 transcripts were ubiquitously expressed in human tissues, La1' transcripts were predominantly expressed in peripheral blood leukocytes, especially in B, T, and natural killer cells. Both La1 and La1' transcripts associated with polysomes in natural killer cells, suggesting that these transcripts were functional mRNAs. Upon activation of B cells with the mitogens phorbol 12-myristate 13-acetate and ionomycin, the amount of La1' mRNA, but not La1, declined. In contrast, after chemical activation of T cells, the amount of La 1 mRNA, but not La1', declined. The mechanism by which the La1 and La1' 5' NCRs initiate translation initiation was tested in cultured human HeLa cells and in two different in vitro translation systems. It was found that both 5' NCRs can mediate translation initiation by internal initiation. These findings indicate that the constitutive expression of La1 mRNA and the tissue-specific expression of La1' mRNA can both allow La protein synthesis under conditions when cap-dependent translation is compromised, such as inflammation, apoptosis, or certain viral infections.

Autoantigens↗
PubMed1992

Interferon-gamma gene expression in human B-cell lines: induction by interleukin-2, protein kinase C activators, and possible effect of hypomethylation on gene regulation.

Human interferon-gamma (IFN-gamma) is an important immunomodulatory protein produced predominantly by T cells and large granular lymphocytes (LGLs). Whereas large amounts of data have been accumulated regarding IFN gamma gene expression in these two cell types, little information about IFN gamma expression in other cell types exists. In this study, we have analyzed the production of IFN gamma by the Epstein-Barr virus (EBV)-positive B-cell line, JLP(c), derived from a patient with Burkitt's lymphoma, and another human B-cell line, PA682BM-1, which was derived from an acquired immunodeficiency syndrome patient. Southern blot analysis indicates the presence of an Ig heavy chain gene rearrangement, but no rearrangement of the T-cell receptor beta chain gene or IFN gamma gene in these B-cell lines. Both cell lines were found to express surface IgD and other B-cell surface markers, thus confirming their B-cell lineage. Analysis for surface Ig, cytoplasmic Ig, and secreted Ig indicates that the two cell lines are in relatively early stages of the B-cell differentiation pathway. We now report that PA682BM-1 can be triggered by the protein kinase C (PKC) activators, phorbol 12-myristate 13-acetate (PMA) and (-)Indolactam-v, to secrete IFN gamma, whereas JLP(c) cells spontaneously produce low levels of IFN gamma that can be enhanced by PKC activators and interleukin-2 (IL-2). After activation of the cell lines with IL-2, (-)Indolactam-v, and PMA, increases in cytoplasmic messenger RNAs (mRNAs) of IFN gamma and the IL-2 receptor chains were also observed. The induction of IFN gamma mRNA and protein by IL-2 was completely blocked by a monoclonal antibody to IL-2 receptor p75 (beta chain), but not by the monoclonal antibody to p55 (alpha chain). Analysis of IFN gamma genomic DNA indicates that the gene is not amplified, but that hypomethylation in the 5' noncoding region of the IFN gamma gene has occurred in the B-cell line from the Burkitt's lymphoma patient that spontaneously produces IFN gamma. This finding suggests that the methylation state of the promoter region may play an important role in the control of IFN gamma gene expression in B cells.

Acquired Immunodeficiency Syndrome↗
PubMed1976

The 3' terminal sequences of human alpha and beta globin messenger RNAs: comparison with rabbit globin messenger RNA.

Sequences of 43 and 70 nucleotides adjacent to the 3' terminal poly(A) of human alpha and beta globin mRNAs have been established. Sequence analysis of complementary DNA from both normal and thalassemic globin mRNA preparations was carried out using endonuclease IV digestion and limited synthesis procedures. The two RNA sequences are 83% homologous to rabbit globin mRNA (Proudfoot, 1976), and a part of the alpha globin mRNA sequence codes for the carboxy terminus of human alpha globin Constant Spring (Clegg, Weatherall, and Milner, 1971). This latter result predicts that the 3' noncoding region of human alpha globin mRNA is exactly 112 nucleotides, while the 5' noncoding region is probably about 50 nucleotides.

Animals↗
PubMed1988

Differential translation of two distinct preprosomatostatin messenger RNAs.

Somatostatin (SRIF) is a 14-amino acid peptide hormone that is present in pancreatic islets and the brain where it is synthesized as a larger precursor, preprosomatostatin. In pancreatic islets of the anglerfish (Lophius americanus), there are two separate precursors, preproSRIF I and preproSRIF II, which give rise to SRIF-14 or an N-terminally extended form SRIF-28, respectively. Significantly higher levels of preproSRIF I compared to preproSRIF II are synthesized in pancreatic islets. We show here that preproSRIF II mRNA possesses an eight-nucleotide repeat (CCAGCAGA) which is present three times in its 5'-noncoding region; this sequence is absent from preproSRIF I mRNA. Progressive deletion of these octameric repeats results in the concomitant enhancement of preproSRIF II mRNA translation in vitro. Furthermore, expression of native or 5'-truncated preproSRIF II mRNA in non-islet tissue culture cells, using a retroviral expression vector, gave identical results to those obtained in vitro, indicating that differential translation was a function of the mRNA rather than the translation system. We propose that the octameric repeat sequence, or a subset of it, is responsible for attenuation of preproSRIF II mRNA translation. Since the differential translation of preproSRIF II mRNA was reproduced in widely divergent systems, this suggests that our results are not related to islet cell gene expression per se. Rather, it is possible they have general significance in that the 5'-repeat sequences may be recognized by putative trans-acting factors involved in the translational regulation of protein synthesis.

Amino Acid Sequence↗
PubMed1990

The complete nucleotide sequence of PEBV RNA2 reveals the presence of a novel open reading frame and provides insights into the structure of tobraviral subgenomic promoters.

The 3374 nucleotide sequence of RNA2 from the British PEBV strain SP5 has been determined. The RNA includes three open reading frames flanked by 5' and 3' noncoding regions of 509 and 480 nucleotides. The open reading frames specify coat protein, a 29.6K product homologous to the 29.1K product of TRV(TCM) RNA2 and a 23K product not homologous to any previously described protein. The homology demonstrated between the coat proteins of PRV, TRV and PEBV indicates a common evolutionary origin for these proteins. Upstream of each ORF are located sequences homologous to those with which subgenomic RNAs of other tobraviruses start. Subgenomic RNAs for the expression of the three ORFs may start at these points. On all five tobraviral RNA2 molecules sequenced to date, these sequences were found upstream of the coat protein ORF in association with a strongly-conserved potential secondary structural element. Similar potential structures were identified upstream of other tobraviral ORFs. These structures may contribute to the activity of the tobraviral subgenomic promoter.

Amino Acid Sequence↗
PubMed1994

The 5'-untranslated regions of picornavirus RNAs contain independent functional domains essential for RNA replication and translation.

The role of the 5'-untranslated region (5'UTR) in the replication of enteroviruses has been studied by using a series of poliovirus type 3 (PV3) replicons containing the chloramphenicol acetyltransferase reporter gene in which the 5'UTR was replaced by the 5'UTR of either coxsackievirus B4 or human rhinovirus 14 or composite 5'UTRs derived from sequences of PV3, human rhinovirus 14, coxsackievirus B4, or encephalomyocarditis virus. The results indicate that efficient replication of an enterovirus genome requires a compatible interaction between the 5'-terminal cloverleaf structure and the coding and/or 3'-noncoding regions of the genome. A crucial determinant of this interaction is the stem-loop formed by nucleotides 46 to 81 (stem-loop d). The independence of the cloverleaf structure formed by the 5'-terminal 88 nucleotides and the ribosome landing pad or internal ribosome entry site (IRES) was investigated by constructing a 5'UTR composed of the PV3 cloverleaf and the IRES from encephalomyocarditis virus. Chloramphenicol acetyltransferase gene-containing replicons and viruses containing this recombinant 5'UTR showed levels of replication similar to those of the corresponding genomes containing the complete PV3 5'UTR, indicating that the cloverleaf and the IRES may be regarded as functionally independent and nonoverlapping elements.

Base Sequence↗
PubMed1986

Structure and expression of the rat insulin-like growth factor II (rIGF-II) gene. rIGF-II RNAs are transcribed from two promoters.

Insulin-like growth factor II (IGF-II) is a mitogenic polypeptide present in rat plasma at high levels during fetal and early postnatal life and is believed to play an important, although as yet undefined, role in fetal development. Both in humans and rats, expression of the IGF-II gene results in the appearance of several mRNA species. In the present study, cDNA and synthetic oligonucleotide probes were used to isolate and characterize the rat IGF-II gene from genomic libraries. The rat IGF-II gene extends over 12 kilobase pairs and contains two 5'-noncoding exons and three protein-coding exons. The two 5' exons represent alternative 5' regions of different mRNA molecules and are expressed from two distinct promoters. The two promoters are transcribed with different efficiencies but exhibit similar tissue-specific expression and regulation with developmental age.

Amino Acid Sequence↗
PubMed1988

The nucleocapsid gene of infectious hematopoietic necrosis virus, a fish rhabdovirus.

The complete nucleotide sequence of the infectious hematopoietic necrosis virus (IHNV) nucleocapsid gene has been determined using cDNA clones of genomic and messenger RNAs. Genomic clones were generated by using random DNA oligomers to prime cDNA synthesis and were mapped to their respective locations on the genome by the use of cDNA probes derived from viral mRNAs. Interesting features of the IHNV nucleocapsid gene sequence elucidated by the sequencing of these clones include short homologies with N genes of other rhabdoviruses at the 5' and 3' nontranslated termini of the mRNA, as well as an exceptionally long 5' noncoding region of the mRNA, suggesting a leader RNA may be coupled to the N mRNA. A comparison of the IHNV N protein coding sequence with other rhabdoviral N genes shows some homologies at the amino acid level which indicates the possible evolutionary relationship of these N proteins. The determination of the nucleotide sequences of IHNV genes and intergenic regions will be useful for studying the mechanisms of rhabdoviral transcription and replication.

Amino Acid Sequence↗
PubMed1985

Multiple gene-like sequences related to the rabbit hepatic progesterone 21-hydroxylase cytochrome P-450 1.

Rabbits exhibit phenotypic differences, 21H and 21L, in the rate of hepatic progesterone 21-hydroxylation that reflect 10-fold higher microsomal concentrations of cytochrome P-450 1 in 21H rabbits. A cDNA library in pBR322 was prepared from liver mRNA isolated from a 21H rabbit. A clone, p1-8, producing a hybrid protein resulting from the insertion of the cDNA into the beta-lactamase gene of the plasmid expressed 5 distinct epitopes that were recognized by a panel of monoclonal antibodies developed toward P-450 1. RNAs selected from total hepatic mRNA by filter hybridization with p1-8 yield at least two electrophoretically distinct proteins when translated in vitro and immunoprecipitated with the 3C3 monoclonal antibody. Only one of the two proteins is recognized by the 1F11 monoclonal antibody, which is highly specific for P-450 1, and the immunoprecipitated protein exhibits the electrophoretic mobility of P-450 1. The other protein remains unidentified. Northern blot analysis indicates that the 3' noncoding portion of p1-8 hybridizes to higher steady state concentrations of polyadenylated RNA in the 21H as compared to 21L rabbits. This correspondence in expression with that of P-450 1 in the 21H and 21L phenotypes further suggests that p1-8 encodes P-450 1 or a closely related protein. The cDNA is 1871 base pairs in length and encodes a protein of 487 amino acids. Southern blot analysis indicates that several independent, gene-like sequences hybridize with the 3' noncoding region of p1-8 under conditions of high stringency. These results indicate that P-450 1 is a member of an extensive multigene family.

Amino Acid Sequence↗
PubMed1986

Cloning and sequence analysis of a cDNA for a rat liver glutathione S-transferase Yb subunit.

We have isolated a Yb-subunit cDNA clone from a GSH S-transferase (GST) cDNA library made from rat liver polysomal poly(A) RNAs. Sequence analysis of one of these cDNA, pGTR200, revealed an open reading frame of 218 amino acids of Mr = 25,915. The deduced sequence is in agreement with the 19 NH2-terminal residues for GST-A. The sequence of pGTR200 differs from another Yb cDNA, pGTA/C44 by four nucleotides and two amino acids in the coding region, thus revealing sequence microheterogeneity. The cDNA insert in pGTR200 also contains 36 nucleotides in the 5' noncoding region and a complete 3' noncoding region. The Yb subunit cDNA shares very limited homology with those of the Ya or Yc cDNAs, but has relatively higher sequence homology to the placental subunit Yp clone pGP5. The mRNA of pGTR200 is not expressed abundantly in rat hearts and seminal vesicles. Therefore, the GST subunit sequence of pGTR200 probably represents a basic Yb subunit. Genomic DNA hybridization patterns showed a complexity consistent with having a multigene family for Yb subunits. Comparison of the amino acid sequences of the Ya, Yb, Yc, and Yp subunits revealed significant conservation of amino acids (approximately 29%) throughout the coding sequences. These results indicate that the rat GSTs are products of at least four different genes that may constitute a supergene family.

Amino Acid Sequence↗