TY - JOUR
T1 - The rRNA operons of Mycobacterium smegmatis and Mycobacterium tuberculosis
T2 - Comparison of promoter elements and of neighbouring upstream genes
AU - Gonzalez-y-Merchand, Jorge A.
AU - Colston, M. Joseph
AU - Cox, Robert A.
PY - 1996/3
Y1 - 1996/3
N2 - Mycobacterium smegmatis has two rRNA (rrn) operons designated rrnA(f) and rrnB(f). Appropriate restriction fragments of genomic DNA containing sequences immediately upstream from the 165 rRNA genes were cloned. We now report the nucleotide sequence of 552 bp upstream from the 5'-end of the Box A(L) antitermination element of the leader region of the rrnA(f) operon. The 5'-end of this segment of DNA was found to comprise 113 codons of an ORF encoding a protein which is significantly similar to UDP-N-acetylglucosamine 1-carboxyvinyl-transferase (EC 2.5.1.7), which is important to cell wall synthesis. A homologous ORF is located immediately upstream from the single rrn (rrnA(s),) operons of Mycobacterium tuberculosis and Mycobacterium leprae. Primer-extension analysis of the RNA fraction of M. smegmatis revealed four products which were related to transcription start points; the rrnB(f) operon appears to have a single promoter whereas the rrnA(f), operon has three (P1, P2 and P3). Analysis of M. tuberculosis RNA revealed two products corresponding to transcripts directed by promoters homologous with p1 and P3 of the rrnA(f) of M. smegmatis. Thus, the promoter and upstream regions of the rrnA(f) operon of M. smegmatis and the rrnA(s) operon of M. tuberculosis are homologous. The presence of P2 in M. smegmatis and its absence from M. tuberculosis is attributable to insertions/deletions of 97 bp.
AB - Mycobacterium smegmatis has two rRNA (rrn) operons designated rrnA(f) and rrnB(f). Appropriate restriction fragments of genomic DNA containing sequences immediately upstream from the 165 rRNA genes were cloned. We now report the nucleotide sequence of 552 bp upstream from the 5'-end of the Box A(L) antitermination element of the leader region of the rrnA(f) operon. The 5'-end of this segment of DNA was found to comprise 113 codons of an ORF encoding a protein which is significantly similar to UDP-N-acetylglucosamine 1-carboxyvinyl-transferase (EC 2.5.1.7), which is important to cell wall synthesis. A homologous ORF is located immediately upstream from the single rrn (rrnA(s),) operons of Mycobacterium tuberculosis and Mycobacterium leprae. Primer-extension analysis of the RNA fraction of M. smegmatis revealed four products which were related to transcription start points; the rrnB(f) operon appears to have a single promoter whereas the rrnA(f), operon has three (P1, P2 and P3). Analysis of M. tuberculosis RNA revealed two products corresponding to transcripts directed by promoters homologous with p1 and P3 of the rrnA(f) of M. smegmatis. Thus, the promoter and upstream regions of the rrnA(f) operon of M. smegmatis and the rrnA(s) operon of M. tuberculosis are homologous. The presence of P2 in M. smegmatis and its absence from M. tuberculosis is attributable to insertions/deletions of 97 bp.
KW - Cell wall synthesis
KW - Pathogenic/non-pathogenic mycobacteria
KW - Promoter activities
KW - UDP N-acetylglucosamine 1-carboxyvinyl-transferase
KW - rRNA operons
UR - http://www.scopus.com/inward/record.url?scp=0029917091&partnerID=8YFLogxK
U2 - 10.1099/13500872-142-3-667
DO - 10.1099/13500872-142-3-667
M3 - Artículo
C2 - 8868442
SN - 1350-0872
VL - 142
SP - 667
EP - 674
JO - Microbiology
JF - Microbiology
IS - 3
ER -