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PubMed2005

The role of simian virus 5 V protein on viral RNA synthesis.

The paramyxovirus simian virus 5 (SV5) has seven genes but encodes eight known viral proteins. The V/P gene is transcribed into two mRNA species: V mRNA from a faithful transcription of the gene and P mRNA from transcription with addition of two G residues at a specific site of the gene. V, a 222-amino acid (AA) residue protein, and P, a 392 AA residue protein, share an identical N-terminus domain of 164 amino acid residues. P is essential for SV5 RNA replication and transcription. Whereas it is known that V plays important roles in virus pathogenesis, the role of V in SV5 replication and transcription is not clear. A mini-genome system, free of vaccinia virus gene expression system, consisting of plasmids expressing NP, P, and L, as well as a plasmid encoding a reporter gene, chloramphenicol acetyltransferase (CAT) flanked by SV5 trailer and leader sequences under control of a bacteriophage T7 RNA polymerase promoter, has been established to examine the role of V in SV5 RNA transcription and replication. Addition of V-expressing plasmid in the mini-genome system caused inhibition of the reporter gene expression, suggesting that V plays a role in regulating SV5 gene expression. By examining the amount of encapsidated viral RNA genome using reverse transcription with primer annealing to viral anti-genome RNA and PCR, it was found that expression of V reduced the amount of viral RNA genome in the mini-genome system, suggesting that V inhibits viral RNA replication. To examine whether the V protein inhibits viral RNA transcription as well, a mini-genome system with a defective anti-genome promoter (AGP) such that a reporter gene (luciferase, Luc) expression is only derived from transcription of newly produced mini-genome and not from de novo replicated viral genome due to the defect in replication element has been utilized. The V protein inhibited luciferase expression from the mini-genome with a defective AGP, suggesting V inhibits SV5 transcription. Thus, SV5 V inhibits both SV5 RNA replication and transcription.

Animals↗

PubMed2005

Completion of the full-length genome sequence of Menangle virus: characterisation of the polymerase gene and genomic 5' trailer region.

Menangle virus (MenV), isolated in 1997 from stillborn piglets during an outbreak of reproductive disease at a large commercial piggery, is the only new paramyxovirus to be identified in Australia since Hendra virus in 1994. Following partial characterisation of the MenV genome, we previously showed that MenV is a novel member of the genus Rubulavirus. Here we report the characterisation of the large (L) polymerase gene and the adjacent 5' trailer region of MenV, which completes the full-length genome sequence of this novel paramyxovirus (15,516 nucleotides), and thereby confirm its taxonomic position within the family Paramyxoviridae.

Amino Acid Sequence↗

PubMed1984

The mitochondrial genome of the fission yeast Schizosaccharomyces pombe. 2. Localization of genes by interspecific hybridization in strain ade7-50h- and cloning of the genome in small fragments.

A series of 18 small overlapping restriction fragments has been cloned, covering the complete mitochondrial genome of Schizosaccharomyces pombe. By hybridizing mitochondrial gene probes from Saccharomyces cerevisiae and Neurospora crassa with restriction fragments of Schizosaccharomyces pombe mitochondrial DNA, the following homologous genes were localized on the mitochondrial genome of S. pombe: cob, cox1, cox2 and cox3, ATPase subunit 6 and 9 genes, the large rRNA gene and both types of open reading frames occurring in mitochondrial introns of various ascomycetes. The region of the genome, hybridizing with cob exon probes is separated by an intervening sequence of about 2500 bp, which is homologous with the first two introns of the cox1 gene in Saccharomyces cerevisiae (class II introns according to Michel et al. 1982). Similarly, in the cox1 homologous region, which covers about 4000 bp, two regions were detected hybridizing with class I intron probes, suggesting the existence of two cox1 introns in Schizosaccharomyces pombe. Hybridization with several specific exon probes with a determined order has revealed that cob, cox1, cox3 and the large rRNA gene are all transcribed from the same DNA strand. The low intensities of hybridization signals suggest a large evolutionary distance between Schizosaccharomyces pombe and Saccharomyces cerevisiae or Neurospora crassa mitochondrial genes. Considering the length of the mitochondrial DNA of Schizosaccharomyces pombe (about 19.4 kbp) and the expected length of the localized genes and intron sequences there is enough space left for encoding the expected set of tRNAs and the small rRNA gene. The existence of leader-, trailer-, ori- and spacer sequences or further unassigned reading frames is then restricted to a total length of about 3000 bp only.

Ascomycota↗

PubMed1979

Nonallelic histone gene clusters of individual sea urchins (Lytechinus pictus): mapping of homologies in coding and spacer DNA.

The linear arrangement and lengths of the spacers and coding regions in the two nonallelic histone gene variant clusters of L. pictus are remarkably homologous by R loop analysis and are similar in general topography to the histone gene repeat units of other sea urchins examined to date. No interventing sequences were detected. The coding regions of these two histone gene variants share considerable sequence homology; however, there are areas of nonhomology in every spacer region and the lengths of the nonhomologous spacers between the H2A and H1 genes are not the same for the two repeat unit classes (inter-gene heterogeneity). Combining length measurements obtained with both R loops and heteroduplexes suggests that the DNA sequences of the analogous leader regions for the two H1 mRNAs are nonhomologous. Similar observations were made for the H4 leader sequences, as well as the trailer region on H2B. S. purpuratus spacer DNA segments share little sequence homology with L. pictus; however, the analgous coding (and possibly flanking) regions have conserved their sequences. The various coding and spacer regions within a repeat unit do not share DNA sequences. Thus certain areas in the sea urchin histone gene repeat units have been highly conserved during evolution, while other areas have been allowed to undergo considerable sequence change not only between species but within a species.

Animals↗

PubMed1995

The complete genome structure and phylogenetic relationship of infectious hematopoietic necrosis virus.

Infectious hematopoietic necrosis virus (IHNV), a member of the family Rhabdoviridae, causes a severe disease with high mortality in salmonid fish. The nucleotide sequence (11,131 bases) of the entire genome was determined for the pathogenic WRAC strain of IHNV from southern Idaho. This allowed detailed analysis of all 6 genes, the deduced amino acid sequences of their encoded proteins, and important control motifs including leader, trailer and gene junction regions. Sequence analysis revealed that the 6 virus genes are located along the genome in the 3' to 5' order: nucleocapsid (N), polymerase-associated phosphoprotein (P or M1), matrix protein (M or M2), surface glycoprotein (G), a unique non-virion protein (NV) and virus polymerase (L). The IHNV genome RNA was found to have highly complementary termini (15 of 16 nucleotides). The gene junction regions display the highly conserved sequence UCURUC(U)7RCCGUG(N)4CACR (in the vRNA sense), which includes the typical rhabdovirus transcription termination/polyadenylation signal and a novel putative transcription initiation signal. Phylogenetic analysis of M, G and L protein sequences allowed insights into the evolutionary and taxonomic relationship of rhabdoviruses of fish relative to those of insects or mammals, and a broader sense of the relationship of non-segmented negative-strand RNA viruses. Based on these data, a new genus, piscivirus, is proposed which will initially contain IHNV, viral hemorrhagic septicemia virus and Hirame rhabdovirus.

Animals↗

PubMed1994

Rapid mRNA degradation in yeast can proceed independently of translational elongation.

We have exploited a modular cat reporter system (Vega Laso, M. R., Zhu, D., Sagliocco, F. A., Brown, A. J. P., Tuite, M. F., and McCarthy, J. E. G. (1993) J. Biol. Chem. 268, 6453-6462) to investigate the relationship between mRNA structure, translation, and stability in the yeast Saccharomyces cerevisiae. The stability of the cat mRNA was not influenced by changes in the length and nucleotide sequence of the 5'-leader, but was affected by the formation of stable 5'-secondary structures (> -15 kcal.mol-1). Cat mRNA stability changed only slightly when the CYC1 3'-trailer was replaced with PGK1 sequences, and was influenced by some secondary structures in the 3'-trailer. Secondary structures formed by interactions between the 5'-leader and 3'-trailer increased the stability of the cat mRNA. However, all of the cat mRNAs studied were intrinsically unstable, having half-lives between 4 and 14 min. The translatability of the cat mRNAs did not correlate with their half-life, and their decay was not blocked by cycloheximide. Therefore, the rapid degradation of the cat mRNA does not seem to depend on translational elongation and is not related in any obvious way to the rate of translational initiation. Furthermore, sequences in the 3'-trailer do not program the rapid decay of the cat mRNA. We discuss the implications of these data in the light of current models of mRNA degradation pathways.

Base Sequence↗

PubMed1989

Stage-specific expression and genomic organization of the actin genes of the malaria parasite Plasmodium falciparum.

Two different actin transcripts are found in the human malaria parasite Plasmodium falciparum. One of these is a 2.5-kb-long RNA found both in asexual blood stages and in the sexual stages (i.e., gametes/zygotes) of the parasite. This transcript is encoded by the P. falciparum (pf)-actin I gene. The second malarial actin gene, the pf-actin II gene, yields a 1.9-kb-long transcript which is formed solely in the sexual stages. Elucidation of the genomic organisation of these two Plasmodium actin genes showed that the pf-actin I gene does not possess any introns whereas the coding region of the pf-actin II gene is interrupted by a 368-bp intron. This intron has consensus splice junction sequences. Nucleotide sequence analysis of the 3' non-coding regions of the pf-actin genes revealed that these regions are quite long (pf-actin I, 250 bp; pf-actin II, 331 bp) and that these trailers do not share sequence similarity. Furthermore, the poly(A)+ addition sites of both actin mRNAs have now been identified. The 5' untranslated regions are also rather long; the sequenced areas lack sequence similarity and have, as do the 3' untranslated regions, a very high A + T content.

Actins↗

PubMed2001

Birth of a retroposon: the Twin SINE family from the vector mosquito Culex pipiens may have originated from a dimeric tRNA precursor.

SINEs are short interspersed repetitive elements found in many eukaryotic genomes and are believed to propagate by retroposition. Almost all SINEs reported to date have a composite structure made of a 5' tRNA-related region followed by a tRNA-unrelated region. Here, we describe a new type of tRNA-derived SINEs from the genome of the mosquito Culex pipiens. These elements, called TWINs, are approximately 220 bp long and reiterated at approximately 500 copies per haploid genome. TWINs have a unique structure compared with other tRNA-SINEs described so far. They consist of two tRNA(Arg)-related regions separated by a 39-bp spacer. Other tRNA-unrelated sequences include a 5-bp leader preceding the left tRNA-like unit and a short trailer located downstream of the right tRNA-like region. This 3' trailer is a 10-bp sequence that is ended by a TTTT motif and followed by a polyA tract of variable length. The right tRNA-like unit also contains a 16-bp sequence which is absent in the left one and appears to be located in the ancestral anticodon stem precisely at a position expected for a nuclear tRNA intron. According to this singular structure, we hypothesize that the TWIN: SINE family originated from an unprocessed polymerase III transcript containing two tRNA sequences. We suggest that some peculiar properties acquired by this dicistronic transcript, such as a polyA tail and a 3' stem-loop secondary structure, promote its retroposition by increasing its chances of being recognized by a reverse transcriptase encoded elsewhere in the C. pipiens genome.

Animals↗

PubMed2005

Genetic comparison of the rhabdoviruses from animals and plants.

There are more than 160 viral species in the Rhabdovidae family, most of which can be grouped into one of the six genera including Vesiculovirus, Lyssavirus, Ephemerovirus, Novirhabdovirus, Cytorhabdovirus, and Nucleorhabdovirus. These viruses are not only morphologically similar but also genetically related. Analysis of viral genes shows that rhabdoviruses are more closely related to each other than to viruses in other families. With the development of reverse genetics, the functions of many cis- and trans-elements important in the process of viral transcription and replication have been clearly defined such as the leader, trailer, and the intergenic sequences. Furthermore, it has been shown that there are two entry sites for the RNA-dependent RNA polymerase: 3' entry for leader synthesis and RNA replication, and direct entry at the N gene start sequence for transcription of the monocistronic mRNAs.

Animals↗

PubMed1999

The 3' end CCA of mature tRNA is an antideterminant for eukaryotic 3'-tRNase.

Cytoplasmic tRNAs undergo posttranscriptional 5' and 3' end processing in the eukaryotic nucleus, and CCA (which forms the mature 3' end of all tRNAs) must be added by tRNA nucleotidyl transferase before tRNA can be aminoacylated and utilized in translation. Eukaryotic 3'-tRNase can endonucleolytically remove a 3' end trailer by cleaving on the 3' side of the discriminator base (the unpaired nucleotide 3' of the last base pair of the acceptor stem). This reaction proceeds despite a wide range in length and sequence of the 3' end trailer, except that mature tRNA containing the 3' terminal CCA is not a substrate for mouse 3'-tRNase (Nashimoto, 1997, Nucleic Acids Res 25:1148-1154). Herein, we extend this result with Drosophila and pig 3'-tRNase, using Drosophila melanogaster tRNAHis as substrate. Mature tRNA is thus prevented from recycling through 3' end processing. We also tested a series of tRNAs ending at the discriminator base (-), with one C added (+C), two Cs added (+CC), and CCA added (+CCA) as 3'-tRNase inhibitors. Inhibition was competitive with both Drosophila and pig 3'-tRNase. The product of the 3'-tRNase reaction (-) is a good 3'-tRNase inhibitor, with a KI approximately two times KM for the normal 3'-tRNase substrate. KI increases with each nucleotide added beyond the discriminator base, until when tRNA+CCA is used as inhibitor, KI is approximately forty times the substrate KM. The 3'-tRNase can thus remain free to process precursors with 3' end trailers because it is barely inhibited by tRNA+CCA, ensuring that tRNA can progress to aminoacylation. The active site of 3'-tRNase may have evolved to make an especially poor fit with tRNA+CCA.

Animals↗

PubMed2006

Residues in two homology blocks on the amino side of the tRNase Z His domain contribute unexpectedly to pre-tRNA 3' end processing.

tRNase Z, which can endonucleolytically remove pre-tRNA 3'-end trailers, possesses the signature His domain (HxHxDH; Motif II) of the beta-lactamase family of metal-dependent hydrolases. Motif II combines with Motifs III-V on its carboxy side to coordinate two divalent metal ions, constituting the catalytic core. The PxKxRN loop and Motif I on the amino side of Motif II have been suggested to modulate tRNase Z activity, including the anti-determinant effect of CCA in mature tRNA. Ala walks through these two homology blocks reveal residues in which the substitutions unexpectedly reduce catalytic efficiency. While substitutions in Motif II can drastically affect k(cat) without affecting k(M), five- to 15-fold increases in k(M) are observed with substitutions in several conserved residues in the PxKxRN loop and Motif I. These increases in k(M) suggest a model for substrate binding. Expressed tRNase Z processes mature tRNA with CCA at the 3' end approximately 80 times less efficiently than a pre-tRNA possessing natural sequence of the 3'-end trailer, due to reduced k(cat) with no effect on k(M), showing the CCA anti-determinant to be a characteristic of this enzyme.

Alanine↗

PubMed2001

The plant tRNA 3' processing enzyme has a broad substrate spectrum.

To elucidate the minimal substrate for the plant nuclear tRNA 3' processing enzyme, we synthesized a set of tRNA variants, which were subsequently incubated with the nuclear tRNA 3' processing enzyme. Our experiments show that the minimal substrate for the nuclear RNase Z consists of the acceptor stem and T arm. The broad substrate spectrum of the nuclear RNase Z raises the possibility that this enzyme might have additional functions in the nucleus besides tRNA 3' processing. Incubation of tRNA variants with the plant mitochondrial enzyme revealed that the organellar counterpart of the nuclear enzyme has a much narrower substrate spectrum. The mitochondrial RNase Z only tolerates deletion of anticodon and variable arms and only with a drastic reduction in cleavage efficiency, indicating that the mitochondrial activity can only cleave bona fide tRNA substrates efficiently. Both enzymes prefer precursors containing short 3' trailers over extended 3' additional sequences. Determination of cleavage sites showed that the cleavage site is not shifted in any of the tRNA variant precursors.

Anticodon↗

PubMed1992

Structure and expression of the ABF1-regulated ribosomal protein S33 gene in Kluyveromyces.

The abundant multifunctional protein ABF1 of Saccharomyces cerevisiae binds to the upstream region of several genes, including some ribosomal protein genes like the one encoding protein S33. Deletion of the ABF1-binding sequence lowers the transcription of these genes three- to more than ten-fold. We have isolated the S33 genes of two related yeast species, Kluyveromyces lactis and Kluyveromyces marxianus. Comparison of the nucleotide sequences of these S33 genes with their counterpart from S. cerevisiae shows a strong sequence similarity covering the whole of the coding regions. In contrast, little or no sequence similarity is found in the 5'-flanking regions of the three genes. Also the trailer regions differ considerably in both length and sequence from one species to another. An ABF1-binding site is present in the upstream region of the S33 gene of K. marxianus. Retardation analyses showed that this sequence is able to bind a protein present in Kluyveromyces cells with a molecular mass somewhat lower than that of S. cerevisiae ABF1. Functional analyses, using a beta-glucuronidase reporter system, showed that the ABF1-binding site is indeed involved in transcription activation of the K. marxianus S33 gene in Kluyveromyces cells. A S. cerevisiae ABF1-gene-specific probe showed only weak hybridization with Kluyveromyces DNA and Northern blots did not show a signal. These results indicate that S. cerevisiae and Kluyveromyces contain functionally related but structurally dissimilar ABF1-type proteins.

Amino Acid Sequence↗

PubMed2001

The inhibitory effect of the autoantigen La on in vitro 3' processing of mammalian precursor tRNAs.

Mammalian tRNA 3' processing endoribonuclease (3' tRNase) can remove a 3' trailer from various precursor (pre)-tRNAs. We investigated what effect the autoantigen La has on 3' processing, since the La protein is known to bind to a 3'-terminal uridine tract of pre-tRNAs. We tested sixteen different pre-tRNA(Arg) substrates containing various 3' trailers with or without a 5' leader sequence for in vitro processing by pig 3' tRNase, and for gel-retardation in the presence or absence of human La protein. The R-TUUU series consists of four pre-tRNAs containing 6, 8, 11 and 15 nt 3' trailers ending with UUU and no 5' leader, while the R-TAGC series consists of the same four pre-tRNAs as R-TUUU except that the terminal sequence is AGC. The R-6LTUUU and R-6LTAGC series are derived from R-TUUU and R-TAGC, respectively, by adding a 6 nt 5' leader. La differentially inhibited their processing and bound to the pre-tRNAs; the 50 % inhibitory concentrations for the R-TUUU, R-TAGC, R-6LTUUU, and R-6LTAGC series were 82 to >850, >850, 2 to 292 and 573 to 785 nM, respectively, and the dissociation constants were 10 to 840, >850, 3 to 203 and 155 to 520 nM, respectively. These results indicate that both the terminal sequence UUU and the 5' leader contribute to more severe inhibition of 3' processing via tighter interaction with La. With respect to the R-TUUU and R-6LTUUU series, on the whole, the La inhibition was enhanced as the 3' trailer lengths decreased. Taken together, our results suggest that the La protein sterically hinders 3' tRNase from binding a pre-tRNA molecule probably near the cleavage site.

Animals↗

PubMed1992

Cleavage specificity of chloroplast and nuclear tRNA 3'-processing nucleases.

tRNAs in eukaryotic nuclei and organelles are synthesized as precursors lacking the 3'-terminal CCA sequence and possessing 5' (leader) and 3' (trailer) extensions. Nucleolytic cleavage of the 3' trailer and addition of CCA are therefore required for formation of functional tRNA 3' termini. Many chloroplast tRNA genes encode a C at position 74 which is not removed during processing but which can be incorporated as the first base of the CCAOH terminus. Sequences downstream of nucleotide 74, however, are always removed. Synthetic yeast pre-tRNA(Phe) substrates containing the complete CCA74-76 sequence were processed with crude or partially purified chloroplast enzyme fractions. The 3'-extended substrates (tRNA-CCA-trailer) were cleaved exclusively between nucleotides 74 and 75 to give tRNA-COH, whereas a 3'-mature transcript (tRNA-CCAOH) was not cleaved at all. A 5'-, 3'-extended chloroplast tRNA-CAG-trailer was also processed entirely to tRNA-COH. Furthermore, a 5'-mature, 3'-extended yeast pre-tRNA(Phe) derivative, tRNA-ACA-trailer, in which C74 was replaced by A, was cleaved precisely after A74. In contrast, we found that a partially purified enzyme fraction (a nuclear/cytoplasmic activity) from wheat embryo cleaved the 3'-extended yeast tRNA(Phe) precursors between nucleotides 73 and 74 to give tRNA(OH). This specificity is consistent with that of all previously characterized nuclear enzyme preparations. We conclude that (i) chloroplast tRNA 3'-processing endonuclease cleaves after nucleotide 74 regardless of the nature of the surrounding sequences; (ii) this specificity differs from that of the plant nuclear/cytoplasmic processing nuclease, which cleaves after base 73; and (iii) since 3'-mature tRNA is not a substrate for either activity, these 3' nucleases must require substrates possessing a 3'-terminal extension that extends past nucleotide 76. This substrate specificity may prevent mature tRNA from counterproductive cleavage by the 3' processing system.

Base Sequence↗

PubMed1997

Distribution of both lengths and 5' terminal nucleotides of mammalian pre-tRNA 3' trailers reflects properties of 3' processing endoribonuclease.

Mammalian tRNA 3'processing endoribonuclease (3'tRNase) removes 3'extra nucleotides after the discriminator from tRNA precursors. Here I examined how the length of a 3'trailer and the nucleotides on each side of the cleavage site affected 3'processing efficiency. I performed in vitro 3'processing reactions of pre-tRNAArgs with various 3'trailers or various discriminator nucleotides using 3'tRNase purified from mouse FM3A cells or pig liver. On the whole, the efficiency of pre- tRNAArg3'processing by mammalian 3'tRNase decreased as the 3'trailer became longer, except in the case of a 3'trailer composed of CC, CCA or CCA plus 1 or 2 nucleotides, which was not able to be removed at all. The distribution of 3'trailer lengths deduced from mammalian nuclear tRNA genomic sequences reflects this property of 3'tRNase. The cleavage efficiency of pre-tRNAArgs varied depending on the 5'end nucleotide of a 3'trailer in the order G approximately A > U > C. This effect of the 5'end nucleotide was independent of the discriminator nucleotides. The distribution of the 5'end nucleotides of mammalian pre-tRNA 3'trailers reflects this differential 3'processing efficiency.

Animals↗

PubMed2005

Complete nucleotide sequence of the hirame rhabdovirus, a pathogen of marine fish.

Reverse transcription-polymerase chain reaction (RT-PCR) derived clones were constructed for the hirame rhabdovirus (HIRRV) CA-9703 strain from Korea, and the DNA was sequenced. The 3'-end of genomic RNA was cloned by poly(A)-tailing of the genomic RNA before reverse transcription, and the 5'-end of the genome was cloned by poly(G)- or poly(C)-tailing of the first strand, followed by PCR. The remainder of the genomic DNA was cloned by reverse transcription-polymerase chain reaction using primers that were based on the published rhabdovirus sequences. The complete genome of HIRRV CA-9703 strain comprises 11,034 nucleotides and encodes six genes in the order of: 3'-leader, N, P, M, G, NV, L, and 5'-trailer. These genes are separated by conserved sequences or gene junctions, with one-nucleotide gene spacers. The first 16 of the 19 nucleotides at the ends of the HIRRV genome are complementary, and the first four nucleotides at the 3'-ends of the HIRRV, infectious hematopoietic necrosis virus (IHNV), viral hemorrhagic septicemia virus (VHSV), and snakehead rhabdovirus (SHRV) genomes are identical. The HIRRV proteins share the highest amino acid sequence homology (ranging from 72% to 92%) with the proteins of IHNV, of all the known fish rhabdoviruses, and the highest sequence homology with respect to the L protein was shared among HIRRV, IHNV, VHSV, and SHRV. Although there were differences in the degrees of relatedness, phylogenetic trees that were derived from multiple sequence alignments of the rhabdovirus proteins showed similar patterns of relationship among these viruses, in which fish Novirhabdoviruses formed a separate clade from spring viremia of carp virus (SVCV), unassigned fish rhabdovirus that was closer to mammalian rhabdoviruses.

Amino Acid Sequence↗

PubMed1984

Structural comparison of yeast ribosomal protein genes.

The primary structure of the genes encoding the yeast ribosomal proteins L17a and L25 was determined, as well as the positions of the 5'- and 3'-termini of the corresponding mRNAs. Comparison of the gene sequences to those obtained for various other yeast ribosomal protein genes revealed several similarities. In all split genes the intron is located near the 5'-side of the amino acid coding region. Among the introns a clear pattern of sequence conservation can be observed. In particular the intron-exon boundaries and a region close to the 3'-splice site show sequence homology. Conserved sequences were also found in the leader and trailer regions of the ribosomal protein mRNAs. The 5'-flanking regions of the yeast ribosomal protein genes appeared to contain sequence elements that many but not all ribosomal protein genes have in common, and therefore may be implicated in the coordinate expression of these genes. The amino acid coding sequences of the ribosomal protein genes show a biased codon usage. Like most yeast ribosomal protein molecules, L17a and L25 are particularly basic at their N-terminus.

Amino Acid Sequence↗