Previous Article | Next Article ![]()
J. Bacteriol., 04 1995, 1699-1702, Vol 177, No. 7
K Singh-Wissmann and JG Ferry
Phosphotransacetylase and acetate kinase catalyze the activation of acetate
to acetyl coenzyme A in the first step of methanogenesis from acetate in
Methanosarcina thermophila. The genes encoding these enzymes (pta and ack)
have been cloned and sequenced. They are arranged on the chromosome with
pta upstream of ack (M.T. Latimer, and J. G. Ferry, J. Bacteriol.
175:6822-6829, 1993). The activities of phosphotransacetylase and acetate
kinase are at least 8- to 11-fold higher in acetate-grown cells than in
cells grown on methanol, monomethylamine, dimethylamine, or trimethylamine.
Northern blot (RNA) analyses demonstrated that pta and ack are transcribed
as an approximately 2.4-kb polycistronic message and that the regulation of
enzyme synthesis occurs at the mRNA level. Primer extension analyses
revealed a transcriptional start site located 27 bp upstream from the
translational start of the pta gene and 24 bp downstream from a consensus
archaeal boxA promoter sequence. S1 nuclease protection assays detected
transcripts with four different 3' ends, each of which mapped to the
beginning of four consecutive direct repeats. Northern blot analysis using
an ack-specific probe detected both the 2.4-kb polycistronic transcript and
a smaller 1.4-kb transcript which is the estimated size of monocistronic
ack mRNA. A primer extension product was detected with an ack-specific
primer; the 5' end of the product was in the intergenic region between the
pta and ack genes but did not follow a consensus archaeal boxA sequence.
This result, as well as detection of an additional 1.4-kb mRNA species,
suggests processing of the polycistronic 2.4-kb transcript.
Copyright © 1995, American Society for Microbiology
Transcriptional regulation of the phosphotransacetylase-encoding and acetate kinase-encoding genes (pta and ack) from Methanosarcina thermophila
Department of Biochemistry and Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0305.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |