Expression of foreign DNA inChlamydomonas reinhardtii

A chimeric octopine synthase-neomycin phosphotransferase (ocs-nptII) gene was used to transform Chlamydomonas reinhardtii to kanamycin resistance. Southern hybridization using DNA isolated from one transformant, T6. 1, indicated that the entire ocs-nptII gene and at least part of the plasmid were integrated into nuclear DNA. Neomycin phosphotransferase II activity has been detected in T6.1 cell extracts. Northern hybridizations, employing a radiolabeled ocs-nptII sequence, revealed a T6.1 transcript approximately the same size as a homologous transcript isolated from E. coli carrying the nptII gene. Although T6.1 is an extremely rare examiple of a stable C. reinhardtii transformant, its occurence nevertheless indicates that bacterial genes can be expressed in the nucleus of the alga.