Copper-dependent reciprocal transcriptional regulation of methane monooxygenase genes in Methylococcus capsulatus and Methylosinus trichosporium

TY - JOUR

T1 - Copper-dependent reciprocal transcriptional regulation of methane monooxygenase genes in Methylococcus capsulatus and Methylosinus trichosporium

AU - Nielsen, AK

AU - Gerdes, K

AU - Murrell, JC

PY - 1997

Y1 - 1997

N2 - The methanotrophic bacteria Methylococcus capsulatus (Bath) and Methylosinus trichosporium OB3b convert methane to methanol using the enzyme, methane monooxygenase (MMO). These bacteria are able to express two distinct MMOs: a cytoplasmic or soluble form (sMMO) and a membrane-bound or particulate form (pMMO). Differential expression of sMMO and pMMO is regulated by the amount of copper ions available to the cells; sMMO is expressed at low copper-biomass ratios, whereas pMMO is expressed at high copper-biomass ratios. In both methanotrophs, transcription of the sMMO gene cluster is negatively regulated by copper ions. Data suggest that transcription of the M. trichosporium OB3b sMMO gene cluster is directed from a sigma(54)-like and a sigma(70)-like promoter. The pMMO (pmo) genes of M. capsulatus (Bath) are transcribed into a polycistronic mRNA of 3.3 kb. The synthesis of this mRNA was activated by copper ions. Activation of pmo transcription by copper ions was concomitant with repression of sMMO gene transcription in both methanotrophs. This suggests that a common regulatory pathway may be involved in the transcriptional switch between sMMO and pMMO gene expression.

AB - The methanotrophic bacteria Methylococcus capsulatus (Bath) and Methylosinus trichosporium OB3b convert methane to methanol using the enzyme, methane monooxygenase (MMO). These bacteria are able to express two distinct MMOs: a cytoplasmic or soluble form (sMMO) and a membrane-bound or particulate form (pMMO). Differential expression of sMMO and pMMO is regulated by the amount of copper ions available to the cells; sMMO is expressed at low copper-biomass ratios, whereas pMMO is expressed at high copper-biomass ratios. In both methanotrophs, transcription of the sMMO gene cluster is negatively regulated by copper ions. Data suggest that transcription of the M. trichosporium OB3b sMMO gene cluster is directed from a sigma(54)-like and a sigma(70)-like promoter. The pMMO (pmo) genes of M. capsulatus (Bath) are transcribed into a polycistronic mRNA of 3.3 kb. The synthesis of this mRNA was activated by copper ions. Activation of pmo transcription by copper ions was concomitant with repression of sMMO gene transcription in both methanotrophs. This suggests that a common regulatory pathway may be involved in the transcriptional switch between sMMO and pMMO gene expression.

U2 - 10.1046/j.1365-2958.1997.4801846.x

DO - 10.1046/j.1365-2958.1997.4801846.x

M3 - Journal article

SN - 0950-382X

VL - 25

SP - 399

EP - 409

JO - Molecular Microbiology

JF - Molecular Microbiology

IS - 2

ER -