Abstract
Plastids originated from photosynthetic bacteria like cyanobacteria, threfore plastid ribosomes belong to the eubacterial 70S class. Furthermore plastid ribosomes have seven plastid-specific ribosomal proteins (PSRPs). PSRPs are conserved across land plants, although their functions remain unknown.
To elucidate the function of PSRP-1, we made psrp-1 disruptant and psrp-1 overexpressing strain of Synechocystis sp. PCC 6803, and examined their growth. The growth of these psrp-1 mutants are the same as wild-type at 30 degrees C on solid medium. However, at 40 degrees C, growth of the psrp-1 disruptant was significantly suppressed in comparison with wild-type and the psrp-1 overexpressing strain. While, in solid medium containing glucose at 30 degrees C, growth of the psrp-1 disruptant was better than that of wild-type, and growth of the psrp-1 overexpressing strain was suppressed. These results suggest that PSRP-1 negatively regulates translation.
