IDENTIFICATION OF GREA ENCODING A TRANSCRIPTIONAL ELONGATION-FACTOR AS A MEMBER OF THE CARA-ORF-CARB-GREA OPERON IN PSEUDOMONAS-AERUGINOSA PAO1

Citation
Cd. Lu et al., IDENTIFICATION OF GREA ENCODING A TRANSCRIPTIONAL ELONGATION-FACTOR AS A MEMBER OF THE CARA-ORF-CARB-GREA OPERON IN PSEUDOMONAS-AERUGINOSA PAO1, Journal of bacteriology, 179(9), 1997, pp. 3043-3046
Citations number
25
Categorie Soggetti
Microbiology
Journal title
ISSN journal
00219193
Volume
179
Issue
9
Year of publication
1997
Pages
3043 - 3046
Database
ISI
SICI code
0021-9193(1997)179:9<3043:IOGEAT>2.0.ZU;2-E
Abstract
A homolog of the transcriptional elongation factor, GreA, was identifi ed in Pseudomonas aeruginosa PAO1. The deduced amino acid sequence for GreA from this organism exhibits 65.2% identity to its counterpart in Escherichia coli K-12. The nucleotide sequence of greA from P. aerugi nosa overlaps by four bases the 3' terminus of carB which encodes the large subunit of carbamoylphosphate synthetase. S1 nuclease experiment s showed that level of the greA transcript is elevated approximately 1 0-fold under conditions of pyrimidine limitation, consistent with the conclusion that transcription is initiated from the previously identif ied pyrimidine-sensitive promoter upstream of the carA-orf-carB-greA o peron. Transcriptional fusion experiments showed the presence of an ad ditional weak promoter within the carB sequence. A greA insertional mu tant of Pseudomonas aerugionsa was constructed by gene replacement. Th e mutant derivative grew well in rich medium but did not grow in minim al medium supplemented by arginine and nucleosides. The greA phenotype was suppressed by secondary mutations at a relatively high rate, cons istent,vith the notion of an important physiological role for GreA.