Abstract
Transcription of the rbcLS operon, encoding RuBisCO, is activated under low-CO2 conditions in the cyanobacterium Synechococcus sp. PCC 7942. A luxAB reporter strain of Synechococcus, carrying a fusion of the DNA segment extending from positions -394 to -13 relative to the translation start site of rbcL and luxAB, showed a 12-fold high level of bioluminescence under low-CO2 condition (0.035% CO2) than under high-CO2 condition (2% CO2). There are three potential CbbR recognition sites in the upstream region of rbcL, two of which were shown to be essential for the low-CO2 responsiveness of the promoter. These results suggested possible involvement of a CbbR-like protein in activation of the rbcLS operon in Synechococcus.
