Transcript analysis of the Halothiobacillus neapolitanus cso operon.
Carboxysomes are polyhedral microcompartments that sequester the CO(2)-fixing enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase in many autotrophic bacteria. Their protein constituents are encoded by a set of tightly clustered genes that are thought to form an operon (the cso operon). This study is the first to systematically address transcriptional regulation of carboxysome protein expression. Quantification of transcript levels derived from the cso operon of Halothiobacillus neapolitanus, the sulfur oxidizer that has emerged as the model organism for carboxysome structural and functional studies, indicated that all cso genes are transcribed, albeit at different levels. Combined with comparative genomic evidence, this study supports the premise that the cso gene cluster constitutes an operon. Characterization of transcript 5'- and 3'-ends and examination of likely regulatory sequences and secondary structure elements within the operon suggested potential strategies by which the vastly different levels of individual carboxysome proteins in the microcompartment could have arisen.
Cai
Fei
F
Department of Chemistry and Biochemistry, The University of Southern Mississippi, Hattiesburg, MS 39406-0001, USA.
Heinhorst
Sabine
S
Shively
Jessup M
JM
Cannon
Gordon C
GC
D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002245:Carbon Dioxide / Q000378:metabolism; D044222:Halothiobacillus / Q000201:enzymology* / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D009876:Operon; D017433:Protein Structure, Secondary; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D002245:Carbon Dioxide