Biogenesis and assembly of the chloroplast ATP synthase of Chlamydomonas reinhardtii: study of mutants with new phenotypes

D. Drapier, X. Johnson, Y. Choquet and F.A. Wollman

UMR7141, IBPC, 13 rue P et M Curie 75005 Paris, France

Our study of a large set of Chlamydomonas mutants where the synthesis of one of the 9 subunits of the chloroplast ATPsynthase is impaired, improves our knowledge of the regulation of expression of ATPsynthase genes. We will present preliminary data on nuclear mutants selected from a collection of insertional mutants of Chlamydomonas gathered by Rachel Dent and Coworkers (2005), two of which display a destabilization of the atpA or atpB transcript. We will also describe a nuclear mutant selected from an insertional mutagenesis conducted by X. Johnson in our laboratory (Johnson et al., 2008) that accumulates reduced amounts of subunit ε . We will discuss the mechanism of the CES regulation in the biogenesis of the chloroplast ATPsynthase: a CES cascade involves the presence of the α,β and γ subunits of CF1 (Drapier et al., 2007), whereas another CES process participates in the biogenesis of CF0 and involves subunits III and IV. Based on a comparative analysis of the phenotypes of these new mutants with those from mutants we described previously (Lemaire et al., 1989), we will investigate the possible role of other ATP synthase subunits in the CES-controlled biogenesis of this enzyme.   Dent et al (2005), Plant Physiol.,137, 545-556. Johnson et al (2008),Photosynthesis.Energy from the sun :14th International congress on photosynthesis,1099-1103. Lemaire and Wollman (1989), JBC,264,10235-10242. Drapier et al. (2007),EMBO, 26, 3581-3591

e-mail address of presenting author: drapier@ibpc.fr