Rapid recovery of chloroplast mutations affecting ribulosebisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii.
Based on the unique ability of chloroplast genes to recombine in Chlamydomonas reinhardtii, a collection of acetate-requiring mutants was screened for recombination with a mutation affecting ribulose-1,5-bisphosphate carboxylase/oxygenase [Rbu-1,5-P(2) carboxylase/oxygenase; 3-phospho-D-glycerate carboxy-lyase (dimerizing), EC 4.1.1.39]. This chloroplast mutation, rcl-u-1-10-6C, causes the absence of Rbu-1,5-P(2) carboxylase/oxygenase activities and alters the isoelectric point of the larger subunit. Several mutants that displayed little or no recombination with 10-6C were recovered, and two lacked carboxylase activity. These new chloroplast mutants lack both large and small Rbu-1,5-P(2) carboxylase/oxygenase subunits. The approach demonstrated here permits the routine recovery of chloroplast mutations affecting this enzyme. Multiple mutations in the Rbu-1,5-P(2) carboxylase/oxygenase large-subunit gene can be used to investigate the function and regulation of this enzyme and the regulation of chloroplast genes in general.
Department of Agronomy, University of Illinois, Urbana, IL 61801.
R J
RJ
Spreitzer
W L
WL
Ogren