scholarly journals Polymorphism of Genetic Ambigrams

2021 ◽  
Author(s):  
Gytis Dudas ◽  
Greg Huber ◽  
Michael Wilkinson ◽  
David Yllanes

AbstractDouble synonyms in the genetic code can be used as a tool to test competing hypotheses regarding ambigrammatic narnavirus genomes. Applying the analysis to recent observations of Culex narnavirus 1 and Zhejiang mosquito virus 3 ambigrammatic viruses indicates that the open reading frame on the complementary strand of the segment coding for RNA-dependent RNA polymerase does not code for a functional protein. Culex narnavirus 1 has been shown to possess a second segment, also ambigrammatic, termed ‘Robin’. We find a comparable segment for Zhejiang mosquito virus 3, a moderately diverged relative of Culex narnavirus 1. Our analysis of Robin polymorphisms suggests that its reverse open reading frame also does not code for a protein. We make a hypothesis about its role.

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 231 ◽  
Author(s):  
Jia Zhou ◽  
Yuhua Wang ◽  
Xiaofei Liang ◽  
Changping Xie ◽  
Wenbo Liu ◽  
...  

Here, we report a novel (+) ssRNA mycovirus, Phoma matteucciicola ourmia-like virus 1 (PmOLV1), isolated from Phoma matteucciicola strain LG915-1. The genome of PmOLV1 was 2603 nucleotides long and contained a single open reading frame (ORF), which could be translated into a product of RNA-dependent RNA polymerase (RdRp) by both standard and mitochondrial genetic codons. Cellular fractionation assay indicated that PmOLV1 RNAs are likely more enriched in mitochondria than in cytoplasm. Phylogenetic analysis indicated that PmOLV1 is a new member of the genus Penoulivirus (recently proposed) within the family Botourmiaviridae.


2002 ◽  
Vol 76 (14) ◽  
pp. 7322-7328 ◽  
Author(s):  
W. Paul Duprex ◽  
Fergal M. Collins ◽  
Bert K. Rima

ABSTRACT Measles virus (MV) is the type species of the Morbillivirus genus and its RNA-dependent RNA polymerase complex is comprised of two viral polypeptides, the large (L) and the phospho- (P) proteins. Sequence alignments of morbillivirus L polymerases have demonstrated the existence of three well-conserved domains (D1, D2, and D3) which are linked by two variable hinges (H1 and H2). Epitope tags (c-Myc) were introduced into H1 and H2 to investigate the tolerance of the variable regions to insertions and to probe the flexibility of the proposed domain structures to spatial reorientation. Insertion into H1 abolished polymerase activity whereas introduction into H2 had no effect. The open reading frame of enhanced green fluorescent protein was also inserted into the H2 region of the MV L gene to extend these observations. This resulted in a recombinant protein that was both functional and autofluorescent, although the overall polymerase activity was reduced by over 40%. Two recombinant viruses which contained the chimeric L genes EdtagL(MMc-mycM) and EdtagL(MMEGFPM) were generated. Tagged L proteins were detectable, by indirect immunofluorescence in the case of EdtagL(MMc-mycM) and by autofluorescence in the case of EdtagL(MMEGFPM). We suggest that D3 enjoys a limited conformational independence from the other domains, indicating that the L polymerases of the Mononegavirales may function as multidomain proteins.


2001 ◽  
Vol 75 (6) ◽  
pp. 2818-2824 ◽  
Author(s):  
Cheng-Yen Huang ◽  
Yih-Leh Huang ◽  
Menghsiao Meng ◽  
Yau-Heiu Hsu ◽  
Ching-Hsiu Tsai

ABSTRACT The 3′ untranslated region (UTR) of bamboo mosaic potexvirus (BaMV) genomic RNA was found to fold into a series of stem-loop structures including a pseudoknot structure. These structures were demonstrated to be important for viral RNA replication and were believed to be recognized by the replicase (C.-P. Cheng and C.-H. Tsai, J. Mol. Biol. 288:555–565, 1999). Electrophoretic mobility shift and competition assays have now been used to demonstrate that theEscherichia coli-expressed RNA-dependent RNA polymerase domain (Δ893) derived from BaMV open reading frame 1 could specifically bind to the 3′ UTR of BaMV RNA. No competition was observed when bovine liver tRNAs or poly(I)(C) double-stranded homopolymers were used as competitors, and the cucumber mosaic virus 3′ UTR was a less efficient competitor. Competition analysis with different regions of the BaMV 3′ UTR showed that Δ893 binds to at least two independent RNA binding sites, stem-loop D and the poly(A) tail. Footprinting analysis revealed that Δ893 could protect the sequences at loop D containing the potexviral conserved hexamer motif and part of the stem of domain D from chemical cleavage.


1999 ◽  
Vol 10 (04) ◽  
pp. 635-643 ◽  
Author(s):  
AGNIESZKA GIERLIK ◽  
PAWEŁ MACKIEWICZ ◽  
MARIA KOWALCZUK ◽  
STANISŁAW CEBRAT ◽  
MIROSŁAW R. DUDEK

Coding sequences of DNA generate Open Reading Frames (ORFs) inside them with much higher frequency than random DNA sequences do, especially in the antisense strand. This is a specific feature of the genetic code. Since coding sequences are selected for their length, the generated ORFs are indirect results of this selection and their length is also influenced by selection. That is why ORFs found in any genome, even much longer ones than those spontaneously generated in random DNA sequences, should be considered as two different sets of ORFs: The first one coding for proteins, the second one generated by the coding ORFs. Even intergenic sequences possess greater capacity for generating ORFs than random DNA sequences of the same nucleotide composition, which seems to be a premise that intergenic sequences were generated from coding sequences by recombinational mechanisms.


Author(s):  
Feroza Begum ◽  
Debica Mukherjee ◽  
Sandeepan Das ◽  
Dluya Thagriki ◽  
Prem Prakash Tripathi ◽  
...  

1.AbstractThe open reading frame (ORF) 1ab of SARS-CoV2 encodes non-structural proteins involved in viral RNA functions like translation and replication including nsp1-4; 3C like proteinase; nsp6-10; RNA dependent RNA polymerase (RdRp); helicase and 3’-5’ exonuclease. Sequence analyses of ORF1ab unravelled emergence of mutations especially in the viral RdRp and helicase at specific positions, both of which are important in mediating viral RNA replication. Since proteins are dynamic in nature and their functions are governed by the molecular motions, we performed normal mode analyses of the SARS-CoV2 wild type and mutant RdRp and helicases to understand the effect of mutations on their structure, conformation, dynamics and thus function. Structural analyses revealed that mutation of RdRp (at position 4715 in the context of the polyprotein/ at position 323 of RdRp) leads to rigidification of structure and that mutation in the helicase (at position 5828 of polyprotein/ position 504) leads to destabilization increasing the flexibility of the protein structure. Such structural modifications and protein dynamics alterations might alter unwinding of complex RNA stem loop structures, the affinity/ avidity of polymerase RNA interactions and in turn the viral RNA replication. The mutation analyses of proteins of the SARS-CoV2 RNA replication complex would help targeting RdRp better for therapeutic intervention.


2001 ◽  
Vol 75 (3) ◽  
pp. 1211-1219 ◽  
Author(s):  
Lai Wei ◽  
Jason S. Huhn ◽  
Aaron Mory ◽  
Harsh B. Pathak ◽  
Stanislav V. Sosnovtsev ◽  
...  

ABSTRACT The objective of this study was to identify the active form of the feline calicivirus (FCV) RNA-dependent RNA polymerase (RdRP). Multiple active forms of the FCV RdRP were identified. The most active enzyme was the full-length proteinase-polymerase (Pro-Pol) precursor protein, corresponding to amino acids 1072 to 1763 of the FCV polyprotein encoded by open reading frame 1 of the genome. Deletion of 163 amino acids from the amino terminus of Pro-Pol (the Val-1235 amino terminus) caused a threefold reduction in polymerase activity. Deletion of an additional one (the Thr-1236 amino terminus) or two (the Ala-1237 amino terminus) amino acids produced derivatives that were 7- and 175-fold, respectively, less active than Pro-Pol. FCV proteinase-dependent processing of Pro-Pol in the interdomain region preceding Val-1235 was not observed in the presence of a catalytically active proteinase; however, processing within the polymerase domain was observed. Inactivation of proteinase activity by changing the catalytic cysteine-1193 to glycine permitted the production and purification of intact Pro-Pol. Biochemical analysis of Pro-Pol showed that this enzyme has properties expected of a replicative polymerase, suggesting that Pro-Pol is an active form of the FCV RdRP.


2002 ◽  
Vol 277 (40) ◽  
pp. 37139-37146 ◽  
Author(s):  
Madoka Yoshida ◽  
Keiko Kashiwagi ◽  
Gota Kawai ◽  
Akira Ishihama ◽  
Kazuei Igarashi

2000 ◽  
Vol 74 (2) ◽  
pp. 997-1003 ◽  
Author(s):  
Ana I. Soldevila ◽  
Said A. Ghabrial

ABSTRACT The undivided double-stranded RNA (dsRNA) genome ofHelminthosporium victoriae 190S virus (Hv190SV) (genusTotivirus) consists of two large overlapping open reading frames (ORFs). The 5′-proximal ORF encodes a capsid protein (CP), and the downstream, 3′-proximal ORF encodes an RNA-dependent RNA polymerase (RDRP). Unlike the RDRPs of some other totiviruses, which are expressed as a CP-RDRP (Gag-Pol-like) fusion protein, the Hv190SV RDRP is detected only as a separate, nonfused polypeptide. In this study, we examined the expression of the RDRP ORF fused in frame to the coding sequence of the green fluorescent protein (GFP) in bacteria andSchizosaccharomyces pombe cells. The GFP fusions were readily detected in bacteria transformed with the monocistronic construct RDRP:GFP; expression of the downstream RDRP:GFP from the dicistronic construct CP-RDRP:GFP could not be detected. However, fluorescence microscopy and Western blot analysis indicated that RDRP:GFP was expressed at low levels from its downstream ORF in the dicistronic construct in S. pombe cells. No evidence that the RDRP ORF was expressed from a transcript shorter than the full-length dicistronic mRNA was found. A coupled termination-reinitiation mechanism that requires host or eukaryotic cell factors is proposed for the expression of Hv190SV RDRP.


2002 ◽  
Vol 83 (7) ◽  
pp. 1777-1781 ◽  
Author(s):  
María Eugenia Sánchez de la Torre ◽  
Carmelo López ◽  
Oscar Grau ◽  
María Laura García

Citrus psorosis virus (CPsV) causes a citrus disease occurring worldwide. Isolate CPV 4 has a genome with three single-stranded RNAs. The complete sequence of RNA 2 (1643 nucleotides) is reported here. Northern blot hybridization with strand-specific probes showed that most of the encapsidated RNA 2 is of negative polarity, although a small amount of the complementary strand may also be present in particles. The RNA 2 complementary strand contained a single open reading frame encoding a protein of 476 amino acids, which includes a motif resembling a nuclear localization signal. The sequence of this putative protein shows no significant similarity to any other in the databases. In the 3′-terminal untranslated region there is a putative polyadenylation signal. No subgenomic RNAs derived from RNA 2 were detected.


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