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At least 937 records · Page 52Linked to original sources
PubMed1991

Nucleotide sequence of the ilvH-fruR gene region of Escherichia coli K12 and Salmonella typhimurium LT2.

We have sequenced the fruR gene and flanking DNA fragments from Escherichia coli K12 and Salmonella typhimurium LT2. The fruR gene codes for a protein that represses the fru operon and activates the pps gene for PEP synthase. The corresponding open reading frame (ORF) FruR consists of 334 amino acid residues. The ORF contains an amino-terminal helix-turn-helix motif, characteristic of DNA-binding proteins and has similarity to known repressor proteins. The sequence is identical to that of the E. coli shl gene (mnemonic for suppressor-H-linked phenotype). It is flanked upstream by the ilvIH genes and downstream by the pbpB gene in both organisms and by orfB, a gene possibly involved in the regulation of cell division.

Acetolactate Synthase↗
PubMed1986

Mitochondrial gene URFN of Neurospora crassa codes for a long polypeptide with highly repetitive structure.

The mitochondrial DNA of Neurospora crassa contains a long potential gene, designated URFN, which is located immediately downstream from the CO1 gene. These two genes are encoded in different reading frames and overlap by 13 codons. URFN is 633 triplets long and terminates at a UAG stop codon. Its codon usage is atypical for N. crassa mitochondrial exons and introns, and resembles that of the long open reading frame (ORF) of the mitochondrial plasmid present in N. crassa strain Mauriceville. Multiple sequence repetitions occur in the presumptive URFN polypeptide, most notably a seven-times reiterated motif of 16 to 18 amino acid residues length. The hydropathy pattern shows that the N-terminal third of the URFN polypeptide is predominantly apolar and includes several potentially membrane-spanning stretches; the remaining part is hydrophilic. Calculation of the secondary structure predicts a high proportion (47%) of alpha-helix conformation. The longest alpha-helix contains 40 residues. No similarities to other mitochondrial genes or reading frames have been found, except a significant homology over a stretch of 16 amino acid residues between the N-terminal part of URFN and a well-conserved sequence in the C-terminal region of CO1. The repetitive region in URFN resembles a similarly repetitive stretch in an unassigned reading frame from bacteriophage lambda. Three arguments support the view that URFN is translated. The open reading frame has a considerable length; URFN is transcribed into a mRNA including the overlapping CO1 gene; URFN is most probably conserved among all the various Neurospora species examined thus far, strongly suggesting that it codes for an essential protein.

Amino Acid Sequence↗
PubMed2000

Characterization of the 2-ketogluconate utilization operon in Pseudomonas aeruginosa PAO1.

The Pseudomonas aeruginosa protein PtxS negatively regulates its own synthesis by binding to the upstream region of its gene. We have recently identified a 14 bp palindromic sequence within the ptxS upstream region as the PtxS operator site (OP1). In this study, we searched the P. aeruginosa genomic sequence to determine whether this 14 bp sequence exists in other regions of the P. aeruginosa chromosome. Another PtxS operator site (OP2) was located 47 bp downstream of ptxS. DNA gel shift experiments confirmed that PtxS specifically binds to a 520 bp fragment that carries OP2. The DNA segment 3' of OP2 contains four open reading frames (ORF1-ORF4), which code for 29, 32, 48 and 35 kDa proteins respectively. The molecular weight of the products of ORFs 2 and 3 were confirmed by T7 expression experiments. Computer analyses suggest that ORF2 encodes an ATP-dependent kinase; ORF3, a transporter; and ORF4, a dehydrogenase. The predicted product of ORF1 showed no homology to previously identified proteins and contains all the conserved amino acids within the aldose 1-epimerase protein motif. Examination of the ptxs-ORF1 intergenic region (using promoter fusion experiments) showed that no potential promoter exists. An isogenic mutant defective in ORF1 was constructed in the P. aeruginosa strain PAO1. In contrast to its parent strain, the mutant failed to grow on a minimal medium in which 2-ketogluconate was the sole carbon source. Similarly, a previously constructed ptxS isogenic mutant of PAO1 did not grow in a minimal medium containing 2-ketogluconate as the sole carbon source. Furthermore, a plasmid carrying a fragment that contains ptxS and ORFs 1-4 complemented the defect of the previously described P. aeruginosa 2-ketogluconate-negative mutant. In the presence of 10 mM 2-ketogluconate, the in vitro binding of PtxS to a DNA fragment that carries either OP1 or OP2 was inhibited. These results suggest that: (i) ptxS together with the other four ORFs constitute the 2-ketogluconate utilization operon (kgu) in P. aeruginosa. Therefore, ORFs 1-4 were designated kguE, kguK, kguT and kguD respectively. (ii) PtxS regulates the expression of the kgu operon by binding to two operators (OP1 and OP2) within the operon; and (iii) 2-ketogluconate is the molecular inducer of the kgu operon or the molecular effector of PtxS.

Amino Acid Sequence↗
PubMed1994

A complex array of Hpr consensus DNA recognition sequences proximal to the enterotoxin gene in Clostridium perfringens type A.

Enterotoxin production in Clostridium perfringens is both strain dependent and sporulation associated. Underlying these phenotypic observations must lie a genetic and molecular explanation and the principal keys will be held within the DNA sequence both upstream and downstream of the structural gene cpe. In accordance with the above we have sequenced 4.1 kbp of DNA upstream of cpe in the type strain NCTC 8239. A region of DNA extending up to 1.5 kb 5' to cpe is conserved in all enterotoxin-positive strains. This region contains a putative ORF with substantial homology to an ORF in the Salmonella typhimurium IS200 insertion element and, in addition, contains multiple perfect consensus DNA-binding sequences for the Bacillus subtilis transition state regulator Hpr. The detailed structural elements revealed by the sequence analysis are presented and used to develop a new perspective on the molecular basis of enterotoxin production in this important food-poisoning bacterium.

Base Sequence↗
PubMed1989

Identification and sequence analysis of Escherichia coli purE and purK genes encoding 5'-phosphoribosyl-5-amino-4-imidazole carboxylase for de novo purine biosynthesis.

It has been shown that the Escherichia coli purE locus specifying 5'-phosphoribosyl-5-amino-4-imidazole carboxylase in de novo purine nucleotide synthesis is divided into two cistrons. We cloned and determined a 2,449-nucleotide sequence including the purE locus. This sequence contains two overlapped open reading frames, ORF-18 and ORF-39, encoding proteins with molecular weights of 18,000 and 39,000, respectively. The purE mutations of CSH57A and DCSP22 were complemented by plasmids carrying ORF-18, while that of NK6051 was complemented by plasmids carrying ORF-39. Thus, the purE locus consists of two distinct genes, designated purE and purK for ORF-18 and ORF-39, respectively. These genes constitute a single operon. A highly conserved 16-nucleotide sequence, termed the PUR box, was found in the upstream region of purE by comparing the sequences of the purF and purMN operons. We also found three entire and one partial repetitive extragenic palindromic (REP) sequences in the downstream region of purK. Roles of the PUR box and REP sequences are discussed in relation to the genesis of the purEK operon.

Amino Acid Sequence↗
PubMed2000

Cloning, sequencing and analysis of the pucC genes from Rubrivivax gelatinosus strain 151 and Rhodopseudomonas acidophila strain 10050.

The pucC genes of Rubrivivax gelatinosus strain 151 and Rhodopseudomonas acidophila strain 10050 have been identified, cloned and sequenced. In Rubrivivax gelatinosus the arrangement of the pucC gene with regard to the pucBA genes was shown to differ from that found in other species of photosynthetic bacteria. The Rhodopseudomonas acidophila pucC was found downstream of four new pucBA gene pairs, bringing the sequenced pucBA pairs to a total of eight in this strain. The predicted PucC protein sequences were compared to those of PucC from other species and showed high similarity. Similarity was also seen to more distantly related proteins LhaA and orf428 of Rhodobacter capsulatus, orf G115 of Rhodospirillum rubrum and 'orf428' from Synechocystis sp. PCC6803. An analysis of the predicted secondary structure of these proteins is given, and their structural similarity to proteins in the Major Facilitator Superfamily is discussed with regard to their possible function.

Journal Article↗
PubMed1998

The yeast transcription factor genes YAP1 and YAP2 are subject to differential control at the levels of both translation and mRNA stability.

Two forms of post-transcriptional control direct differential expression of the Saccharomyces cerevisiae genes encoding the AP1-like transcription factors Yap1p and Yap2p. The mRNAs of these genes contain respectively one (YAP1 uORF) and two (YAP2 uORF1 and uORF2) upstream open reading frames. uORF-mediated modulation of post-termination events on the 5'-untranslated region (5'-UTR) directs differential control not only of translation but also of mRNA decay. Translational control is defined by two types of uORF function. The YAP1 -type uORF allows scanning 40S subunits to proceed via leaky scanning and re-initiation to the major ORF, whereas the YAP2 -type acts to block ribosomal scanning by promoting efficient termination. At the same time, the YAP2 uORFs define a new type of mRNA destabilizing element. Both post-termination ribosome scanning behaviour and mRNA decay are influenced by the coding sequence and mRNA context of the respective uORFs, including downstream elements. Our data indicate that release of post-termination ribosomes promotes largely upf -independent accelerated decay. It follows that translational termination on the 5'-UTR of a mature, non-aberrant yeast mRNA can trigger destabilization via a different pathway to that used to rid the cell of mRNAs containing premature stop codons. This route of control of non-aberrant mRNA decay influences the stress response in yeast. It is also potentially relevant to expression of the sizable number of eukaryotic mRNAs that are now recognized to contain uORFs.

Base Sequence↗
PubMed2006

Facile approach for constructing TEV insertions to probe protein structure in vivo.

The tobacco etch virus (TEV) protease has been used as a tool to examine protein structure in vivo. TEV cleavage sites (TEVcs) have been introduced via cloning into unique restriction sites or random transposon mutagenesis. We describe a facile, efficient method for introducing TEVcs at precise locations in a gene to test specific predictions about protein structure. The method uses the lamda Red recombination system to construct seamless, in-frame insertions of the TEVcs at any desired location within an open reading frame (ORF). The system was tested using the multifunctional PutA protein Salmonella enterica sv. Typhimurium. The first step involved insertion of a chloramphenicol resistance (Cam(R)) cassette with a transcriptional terminator at the desired location. A second swap then replaces the Cam(R) insertion with the TEVcs. Placing a copy of the lac operon downstream of the putA gene provides a simple counterselection for replacement of the Cam(R) insertion and also provides a reporter gene for monitoring transcription of the mutated gene.

Bacterial Proteins↗
PubMed1997

Human immunodeficiency virus type-1 p24 sequence from an Indian strain: expression in Escherichia coli and implications in diagnostics.

A 637-bp fragment, corresponding to the p24 human immunodeficiency virus (HIV) core protein from the gag ORF, was PCR amplified from DNA isolated from peripheral blood mononuclear lymphocytes (PBML) of an asymptomatic HIV-1 seropositive human subject from Bombay and cloned into PCRScript SK(+). The nucleotide sequence revealed highest homology (98.6%) with the consensus sequence of the HIV-1 B subtype. The 637-bp KpnI-HindIII fragment was cloned downstream from a His6 tag in the pQE30 vector under the control of phage T5 promoter leading to production of a 6XHis-p24 fusion protein in Escherichia coli. It showed an approx. 24-kDa band by SDS-PAGE. The recombinant p24 reacted with serum samples from HIV-infected subjects when tested by Western blot and ELISA.

Amino Acid Sequence↗
PubMed1995

DNA sequence and transcriptional analysis of the glycoprotein M gene of murine cytomegalovirus.

We have characterized the gene encoding the murine cytomegalovirus (MCMV) homologue of the human cytomegalovirus (HCMV) UL100 open reading frame (ORF) that encodes the HCMV glycoprotein M (gM) molecule. It was identified based on its collinearity with MCMV homologues of the HCMV UL99, UL102, UL103 and UL104 ORFs which lie in the HindIII G fragment of the K181 strain of MCMV. Sequencing of a 2.3 kb EcoRI-BamHI subfragment of the EcoRI G fragment adjacent to the EcoRI A fragment revealed the presence of the complete MCMV gM ORF and two incomplete ORFs, which corresponded to homologues of HCMV UL99 and UL102. The MCMV gM ORF consists of 1059 nucleotides and is expressed as a 1.2 kb transcript at late times post-infection. To precisely characterize the gM transcript, the 5' and 3' ends were mapped. It was found that the transcript initiates at nucleotides 740 or 745, and that the site of polyadenylation at nucleotide 1961 occurs downstream of the second potential polyadenylation signal located at nucleotide 1934. Based on these findings the MCMV gM is predicted to consist of 353 residues and when compared with HCMV gM has a 47% level of identity. Of great interest is the finding that the MCMV gM amino acid sequence is completely conserved among six isolates of MCMV that had been shown to exhibit considerable variation both in the MCMV glycoprotein B and the immediate-early 1 gene-encoded pp89 molecule. Thus, this glycoprotein appears to be antigenically conserved.

Amino Acid Sequence↗
PubMed1998

Expression of African swine fever virus envelope protein j13L inhibits vaccinia virus morphogenesis.

The African swine fever virus (ASFV) strain Malawi LIL20/1 open reading frame (ORF) j13L was expressed in vaccinia virus (VV) from a strong synthetic late promoter as either a complete ORF (vSJ1) or lacking codons 1-31 (vSJ2). Each recombinant VV produced a small plaque which rapidly reverted to a normal size upon passage. The yield of infectious virus from a single cycle infection with vSJ1 or vSJ2 was reduced 50- to 100-fold compared to wild-type (wt) and a revertant virus (vSJ5) in which the j13L ORF was removed and the VV thymidine kinase gene restored. PCR analysis of nine spontaneous large plaque revertant viruses, recovered after passage of vSJ1 in BSC-40 cells, showed that six had lost the j13L ORF and the co-inserted beta-galactosidase gene. Three viruses retained the j13L and beta-galactosidase genes, but in each case the j13L protein was not expressed due to a different single base deletion near the 5' end of the j13L coding region which introduced a stop codon a short distance downstream. The formation of intracellular mature virus (IMV) and extracellular enveloped virus was reduced 50- to 75-fold in cells infected with vSJ1 compared to wt VV and revertant vSJ5. Electron microscopy showed aberrant IMV precursor structures in vSJ1-infected cells, and immunoelectron microscopy demonstrated that these structures contained j13L protein. These results indicate that expression of the j13L protein is toxic for VV replication due to interference with VV morphogenesis prior to IMV formation.

African Swine Fever Virus↗
PubMed2000

Genetic linkage of the vanB2 gene cluster to Tn5382 in vancomycin-resistant enterococci and characterization of two novel insertion sequences.

VanB-type vancomycin resistance is encoded by the vanB gene cluster, which disseminates by horizontal gene transfer and clonal spread of vancomycin-resistant enterococci (VRE). Genetic linkage of the vanB gene cluster to transposon Tn5382 and the insertion sequences IS16 and IS256-like has previously been shown. In this study linkage of defined vanB gene cluster subtypes to these elements was examined. All the vanB2 subtype strains studied (n=14) revealed co-hybridization of vanB and Tn5382, whereas the strains of vanB1 (n=8) and vanB3 (n=1) subtypes were Tn5382 negative. Conjugative cotransfer of the vanB2 gene cluster and Tn5382 was demonstrated for two strains. DNA sequencing of the vanX(B)-ORFC region in vanB2 strains confirmed that the vanB2 gene cluster is an integral part of Tn5382. No general pattern of linkage was observed with regard to IS16 and IS256-like. Two novel insertion sequences were identified in specific vanB2 subtype strains. (i) A 1611 bp element (ISEnfa110) was detected in the left flank of Tn5382. Its insertion site, lack of terminal inverted and direct repeats, and two conserved motifs in its putative transposase all conform to the conventions of the IS110 family. (ii) A 787 bp element (ISEnfa200) was detected in the vanS(B)-vanY(B) intergenic region. Its ORF encoded a putative protein with 60-70% identity to transposases of the IS200 family. No further copies of ISEnfa110 were found by colony hybridization of 181 enterococcal isolates, whereas ISEnfa200 was found in four additional vanB2 strains from the USA. The five strains had identical ISEnfa200 element insertion sites, and Tn5382 was located downstream from a pbp5 gene conferring high-level ampicillin resistance. These isolates showed related PFGE patterns, suggesting possible clonal spread of a VRE strain harbouring a Tn5382-vanB2-ISEnfa200 element linked to a pbp5 gene conferring ampicillin resistance.

Animals↗
PubMed1992

Identification of a new gene, tmoF, in the Pseudomonas mendocina KR1 gene cluster encoding toluene-4-monooxygenase.

Five genes, tmoABCDE, encoding toluene-4-monooxygenase (T4MO) were previously mapped to a 3.6-kb region of a 10.2-kb SacI DNA fragment isolated from Pseudomonas mendocina KR1 (K.-M. Yen, M. R. Karl, L. M. Blatt, M. J. Simon, R. B. Winter, P. R. Fausset, H. S. Lu, A. A. Harcourt, and K. K. Chen, J. Bacteriol. 173:5315-5327, 1991). In this report, we describe the identification and characterization of a DNA region in the SacI fragment whose expression enhances the T4MO activity determined by the tmoABCDE gene cluster. This region was mapped immediately downstream of the putative transcription termination sequence previously located at the end of the tmoABCDE gene cluster (Yen et al., J. Bacteriol., 1991) and was found to stimulate T4MO activity two- to threefold when expressed in Escherichia coli or Pseudomonas putida. Determination of the nucleotide sequence of this region revealed an open reading frame (ORF) of 978 bp. Expression of the ORF resulted in the synthesis of an approximately 37-kDa polypeptide whose N-terminal amino acid sequence completely matched that of the product predicted from the ORF. The ORF thus defines a gene, which has now been designated tmoF. The TmoF protein shares amino acid sequence homology with the reductases of several mono- and dioxygenase systems. In addition, the reductase component of the naphthalene dioxygenase system, encoded by the nahAa gene of plasmid NAH7 from P. putida G7, could largely replace the TmoF protein in stimulating T4MO activity, and TmoF could partially replace the NahAa protein in forming active naphthalene dioxygenase. The overall properties of tmoF suggest that it is a member of the T4mo gene cluster and encodes the NADH:ferredoxin oxidoreductase of the T4MO system.

Amino Acid Sequence↗
PubMed1995

Translational inhibition by a human cytomegalovirus upstream open reading frame despite inefficient utilization of its AUG codon.

The second of three short upstream open reading frames (uORF2) in the transcript leader of the human cytomegalovirus gp48 (gpUL4) virion glycoprotein gene inhibits downstream translation approximately 10-fold. Remarkably, this inhibition depends on the amino acid coding information of uORF2. In the current studies we demonstrate that expression of the cistron downstream from uORF2 depends on ribosomes bypassing the uORF2 AUG codon (AUG2) by a leaky scanning mechanism. Replacing the nucleotides surrounding the wild-type AUG2 codon with those optimal for translation initiation reduces downstream translation approximately 10-fold. Analyses of mutants in which uORF2 either overlaps or is in frame with the downstream reading frame reveal that the initiation frequency at the wild-type AUG2 codon is surprisingly low; rather, the majority of ribosomal subunits bypass the wild-type AUG2 codon because of its suboptimal context. We propose a model to explain this unprecedented example of a paradoxically strong inhibitory effect of an upstream ORF despite inefficient utilization of its initiation codon.

Base Sequence↗
PubMed1993

Transcriptional analysis of the Chlamydia trachomatis plasmid pCT identifies temporally regulated transcripts, anti-sense RNA and sigma 70-selected promoters.

We analysed transcription of the DNA region immediately downstream of the origin of replication in the chlamydial plasmid pCT. This region comprises two convergent open reading frames (ORF7, ORF8), encoding putative polypeptides that are homologous to each other and with C-terminal domains typical of the phage integrase family of proteins. Northern blot and RNA 5' end mapping analyses indicated that both ORFs were transcribed in the late phase of the chlamydial replicative cycle. RNA mapping showed the presence of a transcript starting 31 nucleotides (nt) before the ATG start codon of ORF7, and two temporally regulated transcripts starting 59 and 89 nt upstream of the ATG start codon of ORF8. Two abundant RNA species of 225 and 415 nt were also identified as overlapping anti-sense transcripts (AS-RNAs), complementary to the 3' end of ORF8 mRNA, with identical 5' ends but different 3' ends. In vitro and in vivo experiments in Escherichia coli showed that the sigma 70-RNA polymerase complex was capable of initiating RNA synthesis at the same sites as observed in Chlamydia trachomatis for ORF7 and AS-RNA transcripts, but was not able to transcribe ORF8. In accord with this, sequences at -10 and -35 nt upstream of the RNA 5' ends resemble sigma 70 consensus promoters in the case of ORF7 and AS, but not in the case of the two ORF8 transcripts. Therefore, transcription of ORF7 and ORF8 is controlled by different types of promoters.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1997

Isolation and characterization of transcription signal sequences from Streptococcus thermophilus.

Streptococcus thermophilus (ST) chromosomal DNA fragments generated by partial Sau3A digestion were cloned into the unique BamHI site upstream from the promoterless chloramphenicol acetyltransferase (cat) gene of the Escherichia coli (EC)promoter-probe vector pKK520-3. Recombinant plasmids containing ST sequences with transcription-activation activity were isolated from chloramphenicol-resistant (CmR) EC transformants. A promoterless Streptomyces antibioticus melanin biosynthesis operon (melC) was inserted immediately downstream from the ST sequence to identify DNA with strong promoter activity. Several ST transcription-activation sequences, termed STPs, were isolated and subcloned, and their nucleic acid sequences determined. The -10 and -35 consensus sequences were identified in these putative ST promoters. Detailed analysis of STP3306 sequence data revealed two partial open reading frames (ORFs) with high degrees of homology to prokaryotic GTP-binding protein and DNA repair enzyme, thus providing valuable information for further study on DNA maintenance in this important lactic acid bacterium.

Amino Acid Sequence↗
PubMed1990

Similar organization of the sigB and spoIIA operons encoding alternate sigma factors of Bacillus subtilis RNA polymerase.

Bacillus subtilis sigma-B is an alternate sigma factor implicated in controlling stationary-phase gene expression. We characterized the genetic organization and regulation of the region containing the sigma-B structural gene (sigB) to learn which metabolic signals and protein factors govern sigma-B function. sigB lay in an operon with four open reading frames (orfs) in the order orfV-orfW-sigB-orfX, and lacZ gene fusions showed that all four frames were translated in vivo. Experiments with primer extension, S1 nuclease mapping, and lacZ transcriptional fusions found that sigB operon transcription initiated early in stationary phase from a site 32 nucleotides upstream of orfV and terminated 34 nucleotides downstream of orfX. Fusion expression was abolished in a strain carrying an in-frame deletion in sigB, suggesting that sigma-B positively regulated its own synthesis, and deletions in the sigB promoter region showed that sequences identical to the sigma-B-dependent ctc promoter were essential for promoter activity. Fusion expression was greatly enhanced in a strain carrying an insertion mutation in orfX, suggesting that the 22-kilodalton (kDa) orfX product was a negative effector of sigma-B expression or activity. Notably, the genetic organization of the sigB operon was strikingly similar to that of the B. subtilis spoIIA operon, which has the gene order spoIIAA-spoIIAB-spoIIAC, with spoIIAC encoding the sporulation-essential sigma-F. The predicted sequence of the 12-kDa orfV product was 32% identical to that of the 13-kDa SpoIIAA protein, and the 18-kDa orfW product was 27% identical to the 16-kDa SpoIIAB protein. On the basis of this clear evolutionary conservation, we speculate these protein pairs regulate their respective sigma factors by a similar molecular mechanism and that the spoIIA and sigB operons might control divergent branches of stationary-phase gene expression.

Amino Acid Sequence↗
PubMed2005

Eukaryotic translational coupling in UAAUG stop-start codons for the bicistronic RNA translation of the non-long terminal repeat retrotransposon SART1.

Most eukaryotic cellular mRNAs are monocistronic; however, many retroviruses and long terminal repeat (LTR) retrotransposons encode multiple proteins on a single RNA transcript using ribosomal frameshifting. Non-long terminal repeat (non-LTR) retrotransposons are considered the ancestor of LTR retrotransposons and retroviruses, but their translational mechanism of bicistronic RNA remains unknown. We used a baculovirus expression system to produce a large amount of the bicistronic RNA of SART1, a non-LTR retrotransposon of the silkworm, and were able to detect the second open reading frame protein (ORF2) by Western blotting. The ORF2 protein was translated as an independent protein, not as an ORF1-ORF2 fusion protein. We revealed by mutagenesis that the UAAUG overlapping stop-start codon and the downstream RNA secondary structure are necessary for efficient ORF2 translation. Increasing the distance between the ORF1 stop codon and the ORF2 start codon decreased translation efficiency. These results are different from the eukaryotic translation reinitiation mechanism represented by the yeast GCN4 gene, in which the probability of reinitiation increases as the distance between the two ORFs increases. The translational mechanism of SART1 ORF2 is analogous to translational coupling observed in prokaryotes and viruses. Our results indicate that translational coupling is a general mechanism for bicistronic RNA translation.

Amino Acid Sequence↗