ABSTRACT
The effect of the genomic and subgenomic leader sequence of potato leafroll polerovirus on the efficiency of translation of the downstream located genes has been studied. The results obtained in vitro and in vivo indicate that neither leader sequence functions as translational enhancer, a generally important feature of leader sequences. Deletion analyses demonstrated that both leader sequences not only decrease translation of the downstream located genes but also alter the ratio of the synthesized proteins. A correlation between the in vitro and in vivo results can be established in the case of the subgenomic leader sequence.
Subject(s)
Gene Expression Regulation, Viral , Genome, Viral , Luteovirus/genetics , RNA, Spliced Leader/genetics , RNA, Viral/genetics , Solanum tuberosum/virology , Base Sequence , Genes, Reporter/genetics , Genes, Viral/genetics , Glucuronidase/analysis , Glucuronidase/genetics , Molecular Weight , Open Reading Frames/genetics , Protein Biosynthesis , Protoplasts/virology , Transcription, Genetic , Transfection , Viral Proteins/analysis , Viral Proteins/biosynthesis , Viral Proteins/chemistry , Viral Proteins/geneticsABSTRACT
The expression of open reading frames located on the subgenomic RNA (sgRNA) has been studied in an in vitro transcription and translation system. The obtained results indicate: a) translation of sgRNA occurs according to the scanning model since the insertion of palindrome (delta G0 = -61 kcal/mol) prevents the initiation of translation; b) ORF6 is translated by suppression of the stop codon separating ORF4 from ORF6 and the presence of suppressor tRNA is necessary for the readthrough; c) the presence of leader sequence of sgRNA (212 nucleotides) decreases the translation efficiency of ORFs located downstream and it affects the ratio of products of ORF4 and ORF5; d) 3'UTR does not influence on an expression of genes located on the sgRNA.
Subject(s)
Plant Viruses/genetics , Protein Biosynthesis , RNA, Viral/genetics , Solanum tuberosum/virology , Base Sequence , Genome, Viral , Molecular Sequence DataABSTRACT
The nucleotide sequence of a chromosomal DNA fragment located upstream from the cysPTWAM operon of Escherichia coli was established. Sequence analysis indicates the presence of an open reading frame which has been designated ucpA (upstream cys P). The potential protein products exhibits strong sequence homology to the members of a large protein family, short-chain dehydrogenases/reductases. Involvement of Crp, FruR and IHF in the regulation of ucpA transcription in vivo was demonstrated.
Subject(s)
Escherichia coli/genetics , Genes, Bacterial , Oxidoreductases/genetics , Amino Acid Sequence , Bacterial Proteins/genetics , Base Sequence , Molecular Sequence DataABSTRACT
The restriction map of cysE gene of Escherichia coli was established after cloning a mini-Mu-lac bacteriophage containing a plasmid replicon and recloning on pBR322 vector plasmid. Enzyme assays of transformants indicated the lack of autoregulation of cysE gene.
