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W Fiers

Publications and source records attributed to W Fiers.

At least 415 records · Page 23Linked to original sources
PubMed1978

Bacteriophage MS2 RNA: a correlation between the stability of the codon: anticodon interaction and the choice of code words.

The non-random distribution of degenerate code words in Bacteriophage MS2 RNA can be explained partially by considerations of the stability of the codon-anticodon complex in prokaryotic systems. Supporting this hypothesis we note that wobble codons are positively selected in codons having G and/or C in the first two positions. In contrast, wobble codons are statistically less likely in codons composed of A and U in the first two positions. Analyses of nucleotides adjacent to 5' and 3' ends of codons indicate a nonrandom distribution as well. It is thus likely that some elements of RNA evolution are independent of the structural needs of the RNA itself and of the translated protein product.

Anticodon↗
PubMed1978

Nucleotide sequence of the simian virus 40 Hind II + III restriction fragment J and the total amino acid sequence of the major structural protein VP1.

The HindII + III restriction fragment J (Hind-J) represents 4.58% of the simian virus 40 genome. The information present in Hind-J is expressed as part of the major, late 16-S messenger RNA, which codes for the structural protein VP1. The nucleotide sequence of the 240-base-pairs-long Hind fragment J has been determined by analysis of each oligonucleotide from both strands resulting from T1 or pancreatic RNase digestion of RNA transcribed from the DNA and from RNase digestion of ribo-substituted DNA. Large oligonucleotide blocks which could be constructed mainly on the basis of complementarity were subsequently ordered by partial chemical degradation of terminally labeled DNA. This direct DNA sequencing approach also completely confirmed the results obtained by both aforementioned RNase degradation methods. In the strand with the same polarity as the late mRNA, triplets corresponding to termination codons are present in two of the three reading frames. The one open reading frame connects in phase with the open reading frame of the neighboring HindII/ III fragments K, F and G, which have been published previously and which together with Hind-J span the total VP1 gene. Some features of the primary nucleotide sequence of this VP1 gene and the derived VP1 amino acid sequence are discussed.

Amino Acid Sequence↗
PubMed1978

Sequence of 129 nucleotides at the 3'-terminus of encephalomyocarditis virus RNA.

The sequence of 129 nucleotides next to the poly(A) tail of encephalomyocarditis virus RNA has been determined by rapid gel sequencing of cDNA synthesized with DNA polymerase I or reverse transcriptase and a phasing primer, [5'-32P]p(dT)8dC. The sequence is in accord with (a) the pyrimidine tracts which were mapped in blocks along the cDNA, (B) the sequences of seven characteristic T1 RNase oligonucleotides in the RNA transcribed from the cDNA with RNA polymerase, and (c) a limited amount of sequence deduced by partial spleen phosphodiesterase digestion and depurination of endonuclease IV oligonucleotides. The 3' end shows little secondary structure on its own. Ten nonsense codons block all three reading frames such that at least 26 nucleotides do not code for protein. The possible function of a homology A-A-U-A-A-A with other polyadenylated RNAs is discussed.

Base Sequence↗
PubMed1978

Nucleotide sequence of the restriction fragment Hind-F-EcoRI1 of simian-virus-40 DNA (part of the VP1 gene).

The nucleotide sequence of the simian virus 40 (SV40) genome region between the cleavage sites for restriction endonucleases EcoRI (map position 0) and HindII (map position 0.05) has been determined mainly by the partial chemical DNA degradation procedure of Maxam and Gilbert. This fragment represents 5.3% of the genome of SV40 and is located in the late region, internally in the VP1 gene. The message strand shows only one open reading frame for translation into protein, which connects to the one for the preceding fragment. On this basis part of the amino acid sequence of the VP1 protein is presented.

Base Sequence↗
PubMed1978

Complete nucleotide sequence of the simian-virus 40 Hind-G fragment and localisation of the carboxyl terminus of the VP1 protein.

The restriction fragment Hind-G represents 7.0% of the simian virus 40 (SV40) genome. The information present in fragment Hind-G is expressed as part of the major, late 16-S messenger RNA. The complete nucleotide sequence of the fragment Hind-G has now been determined by application of the procedure of Maxam and Gilbert [Proc. Natl Acad. Sci. U.S.A. (1977) 74, 560-564]. It contains 369 nucleotide base pairs. On the basis of the termination code words in the strand with the same polarity as the late mRNA, two illegitimate reading frames can be defined. Therefore the third, open frame must code for the carboxyl terminal part of the VP1 protein. It terminates within fragment Hind-G with a TGA signal. This stop codon is followed by a non-translated region of the mRNA of about 83 nucleotides. The latter contains the sequence A-A-U-A-A-A, common to all other eukaryotic mRNA molecules so far studied. The Hind-G fragment also contains sequences which presumably play a role in the synthesis, processing and/or expression of early mRNA; these aspects are discussed in the following paper.

Amino Acids↗
PubMed1978

Complete nucleotide sequence of SV40 DNA.

The determination of the total 5,224 base-pair DNA sequence of the virus SV40 has enabled us to locate precisely the known genes on the genome. At least 15.2% of the genome is presumably not translated into polypeptides. Particular points of interest revealed by the complete sequence are the initiation of the early t and T antigens at the same position and the fact that the T antigen is coded by two non-contiguous regions of the genome; the T antigen mRNA is spliced in the coding region. In the late region the gene for the major protein VP1 overlaps those for proteins VP2 and VP3 over 122 nucleotides but is read in a different frame. The almost complete amino acid sequences of the two early proteins as well as those of the late proteins have been deduced from the nucleotide sequence. The mRNAs for the latter three proteins are presumably spliced out of a common primary RNA transcript. The use of degenerate codons is decidedly non-random, but is similar for the early and late regions. Codons of the type NUC, NCG and CGN are absent or very rare.

Antigens, Neoplasm↗
PubMed1978

The 3'-Terminal nucleotide sequence of encephalomyocarditis virus RNA.

Poly(A)-containing encephalomyocarditis virus RNA functions as an excellent template for cDNA synthesis in vitro with an RNA-dependent DNA polymerase in the presence of an oligothymidylate primer. Under appropriate conditions, discrete transcripts of increasing chain length were obtained, suitable for sequence analysis. A limited cDNA fragment of 36 nucleotides, primer (dT)10 included, was synthesized when dGTP was omitted from the reaction mixture and its primary structure was elucidated using direct DNA-sequencing methods. The complement corresponds to the 3' end of encephalomyocarditis RNA. The hexanucleotide (5'-3')(A-A-U-A-A-A) found in this sequence is also present in all 3' non-coding regions of poly(A)-containing eukaryotic mRNAs studied until now, in nearly identical positions relative to the poly(A) tail. The possible biological significance of this structural homology is discussed.

Base Sequence↗
PubMed1978

Nucleotide sequence of the simian virus 40 small-t gene.

The nucleotide sequence of the segment of simian virus 40 DNA between standard map positions 0.53 and 0.65, i.e., approximately half of the restriction fragment Hind A, is reported. This segment is located near the beginning of the early region and is transcribed counterclockwise. There is a potential initiating ATG signal at 13 nucleotides from the Hind C-Hind A junction in the strand with the same polarity as the early mRNA. From this signal on, an open reading frame is present which would allow the synthesis of a polypeptide of 174 amino acids until a TAA termination codon is reached at nucleotide 602 (map position 0.547). This polypeptide, revealed by the DNA sequence, corresponds almost certainly to small-t antigen. Correlation of the deduced amino acid sequence with the NH(2)-terminal sequences of small-t and large-T (tumor) antigens of simian virus 40, as established by Paucha et al. [Paucha, E., Mellor, A., Harvey, R., Smith, A. E., Hewick, R. M. & Waterfield, M. D. (1978) [Proc. Natl. Acad. Sci. USA 75, 2165-2169], strongly argues that both proteins are indeed initiated at the ATG triplet. Because the DNA region between 0.547 and 0.534 is blocked for translation in all three reading frames by multiple termination condons, we conclude that the large-T antigen must be coded for by two noncontiguous DNA segments: the segment from 0.65 to around 0.60, which small-t and large-T antigens share, and another segment starting at some point after position 0.534 and continuing counterclockwise until it terminates at map position 0.174. Small-t antigen is methionine-rich and has a remarkably high number of cysteine residues clustered mainly in its COOH-terminal half. It is rich in both basic and acidic residues, the former being slightly in excess.

Antigens, Neoplasm↗
PubMed1978

Localization of the 5' terminus of late SV40 mRNA.

A cap-containing oligonucleotide has been isolated from a T1 ribonuclease hydrolysate of total Simian Virus 40-specific late RNA and its structure has been determined as 7mG(5')ppp(5') mAmpU(m)pUp(Up,Cp)ApGp. This oligonucleotide constitutes the major 5' terminus of both late mRNA species, 16S and 19S. Assuming that viral mRNA "caps" are derived from a 5'-terminal triphosphate or diphosphate, these results mean that late transcription is (mainly) initiated at nucleotide L 308 (numbering system of Simian Virus 40 DNA, cf. Fiers et al. (1978) Nature, 273, 113-120). The cap is followed by a contiguous leader sequence which is at least 194 nucleotides long.

Base Sequence↗
PubMed1978

Nucleotide sequence of part of the simian virus 40 Hind-D restriction fragment. The presumed initiation region of the VP2 gene.

The nucleotide sequence at the beginning of the restriction fragment Hind-D from Simian virus 40 DNA has been derived by partial chemical degradation of (5'-32P)-labeled restriction fragments followed by analysis on polyacrylamide gel according to Maxam and Gilbert [Proc. Natl Acad. Sci. U.S.A. 74, 560-564 (1977)]. The sequence reported here is 140 nucleotides long. It contains an ATG codon which presumably corresponds to the initiator codon of the VP2 protein. This codon is preceded by an untranslated region which shows several interesting features, such as an alternation of (dA+dT)-rich and (dG+dC)-rich blocks.

Base Sequence↗
PubMed1978

Nucleotide sequence of the simian virus 40 Hind-K restriction fragment.

The restriction fragment Hind-K represents 4.2% of the genome of Simian virus 40 (SV40) and is located near the middle of the late region. Its nucleotide sequence is reported here. It was mainly established by analysis of transcription products, synthesized by means of Escherichia coli RNA polymerase and nucleoside triphosphates, one of which was (alpha-32P)-labeled. Strand assignment was possible by hybridization of asymmetric, labeled transcripts of total SV40 DNA to filter-bound Hind-K fragment. Further information and unambiguous confirmation of the sequence was obtained by the use of direct DNA-sequencing methods. For this purpose the fragment was labeled at the 5' ends by means of polynucleotide kinase and [gamma-32P]ATP and redigested with a suitable restriction enzyme. The separated products were then either partially digested with snake venom diesterase for analysis by the 'wandering spot' method or partially degraded with the base-specific reagents dimethylsulphate or hydrazine for direct sequence analysis on gel. The Hind-K sequence is 219 base pairs long. The message strand is particularly rich in adenosine (39%) and purines. The nucleotide sequence cna unambiguously be translated into an amino acid sequence and the N-terminal codon of the viral protein VP1 gene could be identified. The amino-terminal part of VP1 is rich in proline and lysine. The nucleotide sequence of Hind-K codes also for the carboxyl-terminal part of the viral protein VP2 and VP3 genes, which partly overlap the VP1 gene.

Base Sequence↗
PubMed1978

Characterization of the 5'-terminal capped structures of late simian virus 40-specific mRNA.

32P-labeled, late simian virus 40-specific RNA was isoalted from infected CV1 cells and completely degraded with RNase T2 and bacterial alkaline phosphatase. The RNase-resistant material was fractionated two dimensionally and further characterized with Penicillium nuclease and nucleotide pyrophosphatase. Two major 5' termini were identified in late simian virus 40 RNA, namely, 7-methyl Gppp 2',6-dimethyl ApUp and 7-methyl Gppp 2',6-dimethyl Ap 2'-methyl, UpUp. Both 5' termini are present in unfractionated viral RNA as well as in the separated 16S and 19S species. As both caps differ only in secondary modification, it is possible that they are derived from the same site on the DNA. The relatively higher cap II content of the 16S mRNA may be related to its slower rate of turnover.

Base Sequence↗
PubMed1978

Interference with simian virus 40 DNA replication by adenovirus type 2 during mixed infection of monkey cells.

Infection of monkey cells with human adenovirus (Ad) is abortive, but the infection can be enhanced by coinfecting with simian virus 40 (SV40). However, in the coinfected monkey cells, Ad interferes strongly with SV40 DNA biosynthesis. This interference was found to be a reproducible, delicately controlled phenomenon that was proportional to the multiplicity of infection of Ad and dependent on the active expression of the Ad genome. Newly synthesized SV40 DNA was not broken down in cells after delayed superinfection with Ad, and several early events of SV40 infection such as adsorption, penetration, uncoating, induction of cellular DNA synthesis, and enhancement of Ad infection were not markedly influenced by Ad-mediated interference. It is unlikely that interference is simply due to competition between SV40 and Ad for metabolites, enzymes, or replication sites. The interference effect could be partially neutralized by an increase in the multiplicity of coinfecting SV40 or by an increase in the time interval between SV40 infection and Ad coinfection. Interference was shown to be due to the activity of an Ad early gene product. However, the detailed mechanism of this Ad interference is still unclear.

Adenoviruses, Human↗