ABSTRACT
The 8890 nucleotide RNA sequence of shallot virus X (ShVX), a new virus isolated from shallot, has been determined. The sequence contains six open reading frames (ORFs) which encode putative proteins (in the 5' to 3' direction) of M(r) 194528 (ORF1), 26333 (ORF2), 11245 (ORF3), 42209 (ORF4), 28486 (ORF5) and 14741 (ORF6). The ORF1 protein was found to be highly homologous to the putative potexvirus RNA replicases; ORF2, -3, -5 and -6 proteins also have analogues among the potex- and/or carlavirus-encoded proteins. ORF3 is followed by an AUG-lacking frame coding for an amino acid sequence homologous to that of the 7K to 8K proteins of the triple gene block of the above-mentioned viruses. The putative ORF4 protein has no reliable homology with proteins in the database. The results obtained testify that, except for the unique 42K protein gene, the ShVX genome combines a number of elements typical of both carla- and potexviruses.
Subject(s)
Genes, Viral/genetics , Genome, Viral , Plant Viruses/genetics , RNA Viruses/genetics , Viral Proteins/genetics , Viral Structural Proteins/genetics , Amino Acid Sequence , Base Sequence , Capsid/genetics , Cloning, Molecular , DNA Helicases/genetics , Molecular Sequence Data , Open Reading Frames , Plant Viruses/classification , Plants/microbiology , RNA-Dependent RNA Polymerase/genetics , Sequence Homology, Amino AcidABSTRACT
The 8534 nucleotide sequence of the genome of the carlavirus, potato virus M (PVM), has been determined. The sequence contains six large open reading frames (ORFs) and non-coding regions consisting of 75 nucleotides at the 5' end, 70 nucleotides followed by a poly(A) tail at the 3' end and 38 and 21 nucleotides between three large blocks of coding sequences. The ORF beginning at the first initiation codon at nucleotide 76 encodes a polypeptide of 223K which, according to its primary sequence analysis, seems to be a virus RNA replicase. The next coding block consists of three ORFs encoding polypeptides of 25K, 12K and 7K. The third block consists of two ORFs encoding polypeptides of 34K (PVM coat protein) and 11K. The 11K polypeptide contains a pattern resembling the consensus for a metal-binding nucleic acid-binding 'finger'.
Subject(s)
Genes, Viral , Plant Viruses/genetics , RNA, Viral/genetics , Amino Acid Sequence , Base Sequence , Codon , Molecular Sequence Data , Oligonucleotide Probes , Open Reading Frames , Sequence Homology, Nucleic Acid , Solanum tuberosumABSTRACT
On the basis of comparison of the protein sequences of the putative virus-specific replicases, carlaviruses can be placed in the "Sindbis-like" supergroup of plus-stranded RNA viruses. Among these, the amino acid sequences of the replication proteins of potex- and tymoviruses showed the highest similarity to potato virus M. The possible functions of conserved domains are suggested to be methyltransferase, nucleotide-binding domain, and RNA polymerase.
Subject(s)
Plant Viruses/enzymology , RNA-Dependent RNA Polymerase/genetics , Amino Acid Sequence , Molecular Sequence Data , Plant Viruses/genetics , Viral Proteins/geneticsABSTRACT
The nucleotide sequence of the 3'-proximal 2630 nucleotides of potato virus M (PVM) genomic RNA was determined. The sequenced region contained five long open reading frames (ORFs). The ORF nearest to the 3'-terminal pol(A) tail corresponds to a polypeptide of Mr 10,848. This ORF is preceded by one which encodes a protein of Mr 33,906 (34K) which has an amino acid sequence that is very similar in its carboxyterminal part to that of the coat proteins of some potexviruses. Three other ORFs encoding polypeptides of Mr 24,615, 11,983 and 6739 are present in the region 5' to the 34K protein gene. There is extensive similarity between these proteins and the corresponding proteins encoded by the conserved triple gene block in the RNA of potexviruses.
