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Title: Regulation, initiation, and termination of the cenA and cex transcripts of Cellulomonas fimi

Journal Article · · J. Bacteriol.; (United States)
OSTI ID:6410928

The authors characterized the in vivo transcripts of two Cellulomonas fimi genes, which encodes an extracellular endo-..beta..-1,4-glucanase. By Northern blot analysis, cenA mRNA was detected in C. fimi RNA preparations from glycerol- and carboxymethyl cellulose-grown cells but not from glucose-grown cells. In contrast, cex mRNA was detected only in the preparations from carboxymethyl cellulose-grown cells. Therefore, the transcription of these genes is subject to regulation by the carbon source provided to C. fimi. By nuclease SI protection studies with unique 5'-labeled DNA probes and C. fimi RNA isolated in vivo, 5' termini were found 51 and 62 bases before the cenA translational initiation codon and 28 bases before the cex translational initiation codon. S1 mapping with unlabeled DNA probes and C. fimi RNA which had been isolated in vivo but which had been 5' labeled in vitro with guanylyltransferase and (..cap alpha..-/sup 32/P)GTP confirmed that true transcription initiation sites for cenA and cex mRNA had been identified. Comparative analysis of the DNA sequences immediately upstream of the initiation sites of the cenA and cex mRNAs revealed a 30-base-pair region where these two sequences display at least 66% homology. S1 mapping was also used to locate the 3' termini of the cenA and cex transcripts. Three 3' termini were found for cenA messages, whereas only one 3' terminus was identified for cex mRNA. The transcripts of both genes terminate in regions where their corresponding DNA sequences contain inverted repeats.

Research Organization:
Univ. of British Columbia, Vancouver
OSTI ID:
6410928
Journal Information:
J. Bacteriol.; (United States), Vol. 169:2
Country of Publication:
United States
Language:
English