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At least 973 records · Page 54Linked to original sources

PubMed1997

Dissection of the gene of the bifunctional PGK-TIM fusion protein from the hyperthermophilic bacterium Thermotoga maritima: design and characterization of the separate triosephosphate isomerase.

Triosephosphate isomerase (TIM), from the hyperthermophilic bacterium Thermotoga maritima, has been shown to be covalently linked to phosphoglycerate kinase (PGK) forming a bifunctional fusion protein with TIM as the C-terminal portion of the subunits of the tetrameric protein (Schurig et al., EMBO J 14:442-451, 1995). To study the effect of the anomalous state of association on the structure, stability, and function of Thermotoga TIM, the isolated enzyme was cloned and expressed in Escherichia coli, and compared with its wild-type structure in the PGK-TIM fusion protein. After introducing a start codon at the beginning of the tpi open reading frame, the gene was expressed in E.c.BL21(DE3)/ pNBTIM. The nucleotide sequence was confirmed and the protein purified as a functional dimer of 56.5 kDa molecular mass. Spectral analysis, using absorption, fluorescence emission, near- and far-UV circular dichroism spectroscopy were used to compare the separated Thermotoga enzyme with its homologs from mesophiles. The catalytic properties of the enzyme at approximately 80 degrees C are similar to those of its mesophilic counterparts at their respective physiological temperatures, in accordance with the idea that under in vivo conditions enzymes occupy corresponding states. As taken from chaotropic and thermal denaturation transitions, the separated enzyme exhibits high intrinsic stability, with a half-concentration of guanidinium-chloride at 3.8 M, and a denaturation half-time at 80 degrees C of 2 h. Comparing the properties of the TIM portion of the PGK-TIM fusion protein with those of the isolated recombinant TIM, it is found that the fusion of the two enzymes not only enhances the intrinsic stability of TIM but also its catalytic efficiency.

Bacterial Proteins↗

PubMed2001

Methylation and mutational analysis of p27(kip1) in prostate carcinoma.

BACKGROUND: We have previously identified 12p12-13 as a region of frequent genetic loss in prostate carcinoma. A candidate tumor suppressor gene at this locus is the cyclin dependent kinase inhibitor p27(kip1), which has been implicated as a marker of aggressive prostate carcinoma. Herein, we examine metastatic prostate tumors, xenografts, and cell lines for gene inactivation via mutational inactivation or promoter hypermethylation. METHODS: Mutation analysis was performed on metastatic prostate tumors of 18 patients, eight prostate carcinoma cell lines, and 18 xenografts by PCR amplification of the entire open reading frame of p27(kip1). PCR products were sequenced directly using internal primers. Methylation analysis was performed on four cell lines and nine xenografts using direct sequencing of cloned PCR products of bisulfite treated DNA. Presence of a CpG was consistent with methylation of that cytosine in the original sample. RESULTS: With the exception of the previously reported homozygous deletion, no additional mutations were identified. Methylated CpG residues were identified in three xenografts (LuCAP23, LuCAP35, and PC82) and the methylated residues clustered at six sites; the cytosines 69, 149, 191, 286, 349, and 487 base pairs 5' of the ATG start codon. However, no sample demonstrated promotor methylation in all sequenced clones and the number of methylated base pairs ranged from seven to three, not the level usually associated with gene silencing. CONCLUSIONS: Mutational inactivation of p27(kip1) is a rare event in metastatic prostate carcinoma. While CpG methylation does occur, it is an infrequent event and does not appear to be the mechanism of p27(kip1) down regulation in prostate carcinoma.

Cell Cycle Proteins↗

PubMed1993

Expression of HIV-1 nef in yeast: the 27 kDa Nef protein is myristylated and fractionates with the nucleus.

The nef gene of human immunodeficiency virus type 1 (HIV-1) has been expressed in the yeast Saccharomyces cerevisiae to produce native Nef proteins. The proteins of M(r) 27 kDa and 25 kDa, produced by translation from the first and second start codons of the nef gene react with human HIV-1 antisera. Under low-level steady-state expression conditions, Nef27 undergoes myristylation and is targeted to the nuclear fraction while Nef25 is not myristylated and not nuclear localized. When produced rapidly and to high levels, Nef27 is initially present in the cytoplasm as a soluble myristylated protein that later fractionates with the nucleus.

Base Sequence↗

PubMed1994

Promoter analysis of the PDA1 gene encoding the E1 alpha subunit of the pyruvate dehydrogenase complex from Saccharomyces cerevisiae.

The location and sequence of the PDA1 gene, encoding the E1 alpha subunit of the pyruvate dehydrogenase (PDH) complex from Saccharomyces cerevisiae, were determined. The PDA1 gene was located on a 6.2 kb fragment of chromosome V, approximately 18 kb centromere distal to RAD3. Consistent with this, the PDA1 gene was genetically mapped at 4 cM from RAD3. A part of the 6.2 kb fragment of chromosome V was sequenced. The nucleotide sequence contained the PDA1 open reading frame and the entire putative promoter. Computer analysis revealed a putative GCN4 binding motif in the PDA1 promoter. The presence of transcriptional elements was experimentally determined by deletion analysis. To this end, ExoIII deletions were constructed in the 5' to 3' direction of the PDA1 promoter and effects on transcription were determined by Northern analysis. Transcription was unaffected upon deletion to position -190 relative to the ATG start codon. Deletions from position -148 and beyond, however, reduced promoter activity at least 40-fold. Apparently the 42 bp between nucleotides -190 and -148 contain an element essential for transcription. Inactivation of the PDA1 promoter could not be attributed to deletions of a recognizable TATA element or any known yeast regulatory motifs. The possible role of the CCCTT sequence present in the 42 bp region and also in the promoters of the other genes encoding subunits of the PDH complex is discussed.

Amino Acid Sequence↗

PubMed1994

Isolation and sequence analysis of a gene from the linear DNA plasmid pPacl-2 of Pichia acaciae that shows similarity to a killer toxin gene of Kluyveromyces lactis.

The toxin-encoding linear plasmid systems found in Pichia acaciae and Kluyveromyces lactis yeasts appear to be quite similar, both in function and structural organization. By Southern hybridization, a linear plasmid of P. acaciae, pPacl-2, was found to hybridize to the second open reading frame (ORF2) of K. lactis plasmid pGKL1, known to encode the alpha and beta subunits of the K. lactis toxin. A 1.7 kbp segment of pPacl-2 DNA was cloned, sequenced and shown to contain four regions of strong homology to four similarly oriented regions of K. lactis ORF2. This 1.7 kbp fragment also contained an ORF of 1473 bp that could encode a protein of approximately 55.8 kDa. Like the alpha subunit gene of K. lactis ORF2, a very hydrophobic region occurs at the N-terminus, perhaps representing a signal sequence for transport out of the cell. Unlike K. lactis ORF2, however, the encoded polypeptide is much smaller and lacks a recognizable domain common to chitinases. The structure of a toxin that includes the translation product of this P. acaciae ORF would likely be quite different from that of the K. lactis toxin. Analysis of the upstream region of the P. acaciae ORF revealed an upstream conserved sequence identical to that found before ORFs 8 and 9 of pGKL2. A possible hairpin loop structure, as has been described for each of the four K. lactis pGKL1 ORFs, was found just upstream of the presumed start codon. The similarity of the promoter-like elements found in the linear plasmid genes of these diverse yeasts reinforces the idea of the existence of a unique, but highly conserved, expression system for these novel plasmids. The sequence has been deposited in the GenBank data library under Accession Number U02596.

Amino Acid Sequence↗

PubMed2001

Genome organization of the linear cytoplasmic element pPE1B from Pichia etchellsii.

The linear cytoplasmic element pPE1B from Pichia etchellsii CBS2011 (synonym Debaryomyces etchellsii) was totally sequenced. It consists of 12835 bp and has a remarkable high A+T content of 77.3%. The termini of pPE1B were found to consist of inversely orientated identical nucleotide repetitions 161 base pairs long, to which proteins are probably covalently linked at the 5' ends. Ten putative genes (open reading frames, ORFs) were identified, covering 96.5% of the total sequence. The predicted polypeptides correspond to proteins encoded by ORFs 2-11 of the linear plasmids pGKL2 of Kluyveromyces lactis and pSKL of Saccharomyces kluyveri. ORF1, existing on both latter elements, is lacking on pPE1B. An upstream conserved sequence motif (UCS) is located at the expected distance from the start codon of each of the 10 ORFs. As the arbitrarily chosen UCS6 was able to drive expression of a reporter gene in the heterologous pGKL-encoded killer system of K. lactis, extranuclear promoter function is probable. The almost congruent genome organization of pPE1B and other autonomous linear yeast plasmids sequenced so far, i.e. pGKL2 and pSKL, suggests a common, presumably viral, ancestor.

Base Sequence↗

PubMed2002

Basic functional analysis of six unknown open reading frames from Saccharomyces cerevisiae: four from chromosome VII and two from chromosome XV.

Six open reading frames (ORFs) of unknown function from Saccharomyces cerevisiae from the left arms of chromosomes VII and XV were disrupted by the short-flanking homology method in the diploid strains FY1679 and CENPK2. In each case, the entire ORF, with the exception of the first nucleotide of the start codon, was eliminated and replaced by the kanMX4 cassette. Correct integration of the disrupting marker was checked by colony PCR of the geneticin (G418)-resistant transformants. Sporulation followed by tetrad dissection of the diploids revealed that none of the ORFs encoded a product essential for the viability of either yeast strain. The neutral effect of these disruptions extended to mating and sporulation, since it was possible to create homozygous diploid disruptants that were capable of sporulation. Basic phenotypic analysis was carried out on all strains by growing them on three different media at three different temperatures and revealed no significant differences between disruptants and the parental strains. A cognate clone and a kanMX4 disruption cassette were created for five of the six ORFs by gap repair with specific long-flanking homology cassettes. For experimental reasons, the cognate clone and disruption cassette corresponding to the sixth ORF (YGL161w) had to be created by PCR.

Chromosomes, Fungal↗

PubMed2002

Dissection of the promoter of the HAP4 gene in S. cerevisiae unveils a complex regulatory framework of transcriptional regulation.

In S. cerevisiae, the heteromeric Hap2/3/4/5 complex is necessary for induced transcription of a large number of genes involved in oxidative metabolism on non-fermentable carbon sources. The Hap4p subunit is the activator subunit and at the same time also the regulatory part of the complex, since it is the only one whose level is regulated by carbon source itself. HAP4 promoter analysis shows a 265 bp activating region at position -1006/-741 bp upstream of the ATG start codon. Specific and differential protein-binding to a 30 nt CSRE-like sequence within this region was observed with extracts from repressing and inducing carbon sources. Carbon source-dependent activation mediated by the 265 bp fragment, as well as protein binding to the 30 nt CSRE-like region, is dependent on the presence of CAT8 function, unveiling a complex framework by which the expression of the HAP4 gene is coordinated.

Binding Sites↗

PubMed1993

Overproduction of soluble trichodiene synthase from Fusarium sporotrichioides in Escherichia coli.

Trichodiene synthase is a sesquiterpene cyclase isolated from various fungal species which catalyzes the cyclization of farnesyl diphosphate (FPP) to trichodiene. The trichodiene synthase gene (Tox5) of Fusarium sporotrichioides has previously been cloned and expressed as 0.05-0.1% of total cell protein in Escherichia coli. We have used polymerase chain reaction to amplify the trichodiene coding sequence carried on the plasmid pTS56-1. The resulting DNA, carrying a BamHI restriction site and the T7 gene 10 ribosome binding site and translational spacer element immediately upstream of the ATG start codon as well as a HindIII site adjacent to the translational stop codon, was inserted into the corresponding sites of the expression vector pLM1. The latter vector carried the promoter and translational leader sequence from T7 gene 10 and the E. coli rmBT1T2 tandem transcription terminator. This construct was cloned into E. coli BL21 (DE3). The resulting transformants, when induced with isopropyl beta-D-thiogalactoside, produced trichodiene synthase as 20-30% of total soluble protein. The recombinant synthase, which could be purified five-fold to homogeneity by ammonium sulfate precipitation, ion-exchange chromatography on Q Sepharose, and gel filtration on Superose 12, was identical to native protein in steady-state kinetic parameters and mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had the expected MENFP N-terminal sequence.

Base Sequence↗

PubMed1993

Overexpression in Escherichia coli of soluble aristolochene synthase from Penicillium roqueforti.

Aristolochene synthase, a fungal cyclase which has been isolated from Aspergillus terreus and Penicillium roqueforti, catalyzes the cyclization of farnesyl diphosphate to the sesquiterpene hydrocarbon aristolochene. The aristolochene synthase gene (Ari1) of P. roqueforti has previously been cloned and expressed at low levels as a protein A-aristolochene synthase fusion protein in Escherichia coli. We have now used the polymerase chain reaction to amplify the aristolochene synthase coding sequence using engineered primers which produced dsDNA carrying an EcoRI restriction site and the T7 gene 10 ribosome binding site and translational spacer element immediately upstream of the ATG start codon and a BamHI site adjacent to the TAA stop codon. The PCR product was digested with EcoRI and BamHI and inserted into the multiple cloning site of the expression vector pLM1 which carried the promoter and translational leader sequence from T7 gene 10 and the E. coli rrnBT1T2 tandem transcription terminator. Cloning of the resulting construct into E. coli XL1-Blue and subcloning into the expression host E. coli BL21 (DE3) gave transformants which expressed aristolochene synthase at levels up to 40% of soluble protein when induced with isopropyl beta-D-thiogalactoside. Purification of the recombinant protein by ammonium sulfate precipitation, ion-exchange chromatography on Q Sepharose, and affinity dye chromatography on Reactive Blue 4-agarose gave homogenous aristolochene synthase which had the expected N-terminal sequence, ATSTE, mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and steady-state kinetic parameters when compared to native fungal protein.

Base Sequence↗

PubMed1995

Yeast protein geranylgeranyltransferase type-I: overproduction, purification, and characterization.

Protein geranylgeranyltransferase type-I (PGGTase-I) catalyzes alkylation of the cysteine residue in proteins containing a consensus C-terminal CaaX sequence ending in leucine by the C20 hydrocarbon moiety in geranylgeranyl diphosphate (GGPP). The Saccharomyces cerevisiae genes encoding the alpha (RAM2) and beta (CDC43) subunits of PGGTase-I were translationally coupled by overlapping the RAM2-CDC43 stop-start codons and by locating a ribosome-binding site near the 3' end of RAM2. Recombinant PGGTase-I was overproduced in Escherichia coli to give approximately 8% of total cellular protein and purified 12-fold to > 95% homogeneity in two steps by ion-exchange and immunoaffinity chromatography. The purified heterodimer contained alpha- and beta-subunits with molecular masses of 34 and 42 kDa, respectively. A continuous fluorescence assay was developed to measure PGGTase-I activity. The recombinant enzyme showed maximal activity at pH 7.5 and required both Mg2+ and Zn2+. Michaelis constants for GGPP (1.0 microM) and dansyl-Gly-Cys-Ile-Ile-Leu (2.4 microM) were similar to those reported for yeast protein farnesyltransferase (PFTase) with farnesyl diphosphate and dansyl-Gly-Cys-Val-Ile-Ala; Vmax = 0.20 mumol min-1 mg-1 for recombinant yeast PGGTase-I was similar to that reported for yeast PFTase.

Alkyl and Aryl Transferases↗

PubMed1997

Molecular organization of the glutathione reductase gene in Drosophila melanogaster.

Glutathione reductase catalyzes the conversion of the oxidized form of glutathione to regenerate reduced glutathione, which acts as a versatile intracellular reductant. The present study provides initial characterization of the glutathione reductase gene in Drosophila melanogaster and its response to experimentally induced oxidative stress. Drosophila cDNA clones were isolated, based on cross-hybridization to the Musca domestica glutathione reductase cDNA. Genomic clones were isolated by cross-hybridization with the Drosophila cDNA as hybridization probe. Northern analysis of adult Drosophila poly(A)+ RNA, utilizing the Drosophila cDNA probe, revealed a hybridization signal in the 2-kb range. The entire sequence of one cDNA was determined. In addition to a coding domain of 1431 bases, the sequence included 206 bases upstream of a putative start codon and 355 bases downstream of a putative stop codon. Based on the cDNA sequence, the 476 amino acid sequence of the Drosophila glutathione reductase gene was deduced and was found to have extensive similarities with the glutathione reductase gene from other species. Gene mapping of a 13-kb genomic fragment revealed that the glutathione reductase gene consists of at least two exons spanning approximately 5 kb. A first exon contains sequence for only the first 5 amino acids and the first base of the sixth and appears to be separated by a ca. 2.5-kb intron from the remainder of the coding region, which is confined to <2 kb. The Drosophila glutathione reductase is single copy and its cytogenetic position, as determined by in situ hybridization, is 7D-E on the X chromosome. mRNA levels of glutathione reductase, measured by RT-PCR, increased in response to exposure to 100% ambient oxygen by almost twofold and administration of paraquat by greater than threefold. Exposure of flies to hyperoxia also induced a 60% increase in the activity of glutathione reductase and augmented the concentration of total glutathione by ca. 40% following an initial drop. The present study, besides providing an initial molecular characterization of the glutathione reductase gene in Drosophila, demonstrates its dynamic involvement in response to experimentally induced oxidative stress.

Amino Acid Sequence↗

PubMed2000

The Helicobacter pylori pyrB gene encoding aspartate carbamoyltransferase is essential for bacterial survival.

The production of defined isogenic Helicobacter pylori pyrB mutants was undertaken to investigate the role of aspartate carbamoyltransferase (encoded by pyrB) in the survival of the bacterium. The complete structural gene for aspartate carbamoyltransferase from H. pylori strain RU1 was cloned into Escherichia coli by complementation of a pyrB auxotrophic mutant to facilitate the construction of a pyrB-disrupted copy in E. coli. The H. pylori pyrB gene had high similarity to other bacterial pyrB genes, and the phylogenetic clustering with different species was consistent with functional characteristics of the ACTase. The transcription initiation site for H. pylori pyrB-mRNA was mapped 25 bp upstream of the ATG start codon, and potential promoter regions were identified. In order to construct an isogenic pyrB H. pylori mutant by natural transformation and allelic exchange, the plasmid insert containing pyrB was disrupted by insertional mutagenesis of a chloramphenicol transferase gene cassette. In multiple transformations of H. pylori cells, no chloramphenicol-resistant pyrB mutants were isolated. Successful mutagenesis of other H. pylori genes and PCR amplification of the recombined gene demonstrated that the ACTase-negative mutants had been constructed by allelic exchange involving simultaneous replacement of the pyrB gene with the chloramphenicol-pyrB-disrupted copy. These findings suggested that the ACTase enzyme is essential for the survival of H. pylori.

Alleles↗

PubMed1998

Homology-based gene prediction using neural nets.

We have developed and implemented a method for computational gene identification called GIN (gene identification using neural nets and homology information) that has been particularly designed to avoid false positive predictions. It thus predicts 55% of all genes tested correctly, has a specificity of 99%, but also has an overall accuracy of 92% on a benchmark set of 570 vertebrate genes constructed by Burset and Guigo. The method combines homology searches in protein and expressed sequence tag databases with several neural networks designed to recognize start codons, Poly(A) signals, stop codons, and splice sites. Predicted exons are assembled into genes using a homology-based scoring function. GIN is able to recognize multiple genes within genomic DNA as demonstrated by the identification of a globin gene (gamma-globin-1(G)) that has not been annotated as a coding region in the widely used the test set of Burset and Guigo. Furthermore, GIN identifies more than 107 other protein hits in noncoding regions and classifies them into possible pseudogenes or splice variants.

Animals↗

PubMed1998

Molecular study and partial characterization of iron-only hydrogenase in Desulfovibrio fructosovorans.

An iron-only hydrogenase was partially purified and characterized from Desulfovibrio fructosovorans wild-type strain. The enzyme exhibits a molecular mass of 56 kDa and is composed of two distinct subunits HydA and HydB (46 and 13 kDa, respectively). The N-terminal amino acid sequences of the two subunits of the enzyme were determined with the aim of designing degenerate oligonucleotides. Direct and inverse polymerase chain reaction techniques were used to clone the hydrogenase encoding genes. A 9-nucleotide region located 75 bp upstream from the translational start codon of the D. fructosovorans hydA gene was found to be highly conserved. The analysis of the deduced amino acid sequence of these genes showed the presence of a signal sequence located in the small subunit, exhibiting the consensus sequence which is likely to be involved in the specific export mechanism of hydrogenases. Two ferredoxin-like motives involved in the coordination of [4Fe-4S] clusters were identified in the N-terminal domain of the large subunit. The amino acid sequence of the [Fe] hydrogenase from D. fructosovorans was compared with the amino acid sequences from eight other hydrogenases (cytoplasmic and periplasmic). These enzymes share an overall 18% identity and 28% similarity. The identity reached 73% and 69% when the D. fructosovorans hydrogenase sequence was compared with the hydrogenase sequences from Desulfovibrio vulgaris Hildenborough and Desulfovibrio vulgaris oxamicus Monticello, respectively.

Journal Article↗

PubMed1993

Cloning of the rat insulin- like growth factor binding protein-5 gene and DNA sequence analysis of its promoter region.

To understand the regulation of the insulin-like growth factor binding protein-5 (IGFBP-5) gene expression, we have cloned the IGFBP-5 gene from rat genomic libraries and determined its genomic organization as well as the DNA sequence at the 5' flanking region of the gene. The rat IGFBP-5 gene spans at least 17 kilobases (kb) of the genome and contains 4 exons interrupted by 3 introns of approximately 10, 0.6 and 0.7 kb, respectively. Southern blot analysis of the rat chromosome DNA revealed a single copy gene for IGFBP-5 in the haploid genome. Primer extension experiments demonstrated a single transcriptional start site located at 772 nucleotides 5' of the ATG translational start codon. In addition to a TATA box and a CAAT box, multiple putative cis-regulatory elements, including an AP-1, an AP-2 and a binding site for progesterone receptor are present in the promoter region. This finding suggests that the IGFBP-5 gene is one of those that are expressed in a tissue-specific manner.

Amino Acid Sequence↗

PubMed1993

Identification and characterization of the ctaC (coxB) gene as part of an operon encoding subunits I, II, and III of the cytochrome c oxidase (cytochrome aa3) in the cyanobacterium Synechocystis PCC 6803.

The gene (coxII = coxB = ctaC) encoding subunit II of Synechocystis PCC 6803 cytochrome c oxidase has been isolated by screening a genomic DNA library in pUC18 with a 17-bp oligonucleotide probe (probe C) derived from coxI of Paracoccus denitrificans after Southern blots with a 19-kb oligonucleotide (probe A) derived from coxII of P. denitrificans had given equivocal results. A 2.2 kb PstI-KpnI restriction fragment was subcloned into pUC 18 and the resulting plasmid pDAUV26, which contained the probe C-binding site near the downstream end was found also to contain the whole coxII gene upstream of this site. The novel plasmid pDAUV 26 was used to transform competent E. coli cells, propagated therein, and the sequence determined. The 2.2 kb insert contained the entire coding region for the coxII gene together with a GAG start codon, a TAA stop codon, and a putative Shine-Dalgarno sequence. The deduced COII polypeptide is composed of 319 aa (calculated molecular mass of 32,800) plus a N-terminal leader sequence of 20 aa. The hydropathy plot suggests two lipophilic transmembrane domains near the N-terminus connected with an extremely hydrophilic aa stretch on the cytosolic side, while an unusually long (> 50 aa) aa stretch on the periplasmic (= intrathylakoidal) side leads to a typical cyanobacterial threonine in place of the first conserved glutamate of the cytochrome c-binding region in all other COII proteins. Together with a considerably shortened and interrupted aromatic aa stretch in this region, these differences are discussed in terms of the peculiar affinity of cyanobacterial cytochrome oxidases for acidic c-type cytochromes. Other invariant features such as the strictly conserved CuA-binding aa, however, are found in correct positions.

Amino Acid Sequence↗

PubMed1993

Characterization of DNA binding properties of Yp20: an abundant nuclear protein isolated from Saccharomyces cerevisiae.

The aim of this study was to elucidate the function of Yp20 (yeast 20 kDa protein) which is an abundant basic DNA-binding protein copurified with yeast chromatin. The work presented here shows that Yp20 is a sequence specific DNA binding protein. DNA binding activity was extremely thermostable. The affinity of binding to TRP1 was higher than the affinity of binding to the B domain of ARS1. The dissociation half time of Yp20-DNA complexes was less than 1 min. Yp20 showed no homology to a similar abundant 21 kDa ARS binding factor II (ABFII), previously described. Competitive gel retardation assays revealed two different regions that were protected by Yp20. One was overlapping the ABF1 binding site on ARS1 and another protected region was found upstream to the translational start codon of the TRP1 gene. It thus appears that Yp20 may have a role in DNA replication and/or transcription.

Base Sequence↗