REGULATION OF THE EXPRESSION OF PHOTORESPIRATORY GENES OF CHLAMYDOMONAS REINHARDTII A Thesis

ii ACKNOWLEDGMENTS I have gained a vast amount of skill and knowledge throughout my Master of Science study at Louisiana State University. Therefore, I would like to first thank Dr. James V. Moroney, my major professor, for his patience and guidance and also Dr. C. Larkin, my committee members, for their help, guidance and time. I have studied in an environment surrounded by people who have rational, critical and scientific thinking. Moreover, I was surrounded by people who had great empathy, understanding, and teaching abilities. the Office of Graduate Studies, for their time, effort and guidance for me and for the other graduate students in the Department of Biological Sciences. AAT alanine:alpha-ketoglutarate aminotransferase ABC adenosine triphosphate binding cassette BLAST basic local alignment search tool CCP chloroplast carrier protein CAH carbonic anhydrase CAM crassulacean acid metabolism CAP contig assembly program CAT catalase CCM carbon dioxide concentrating mechanism C i inorganic carbon DEPC diethyl pyrocarbonate EST expressed sequence tag GAPDH glyceraldehyde phosphate dehydrogenase GDCH glycine decarboxylase H protein GDCL glycine decarboxylase L protein GDCP glycine decarboxylase P protein GDCT glycine decarboxylase T protein GDH glycolate dehydrogenase GK glycerate kinase GS glutamine synthetase GOGAT glutamine:alpha-ketoglutarate aminotransferase GOX glycolate oxidase ix HPR hydroxypyruvate reductase kDa kilo dalton LCI low CO 2 inducible MIN minimal media ORF open reading frame PCR polymerase chain reaction PEP phosphoenolpyruvate 3-PGA 3-phosphoglycerate PGP phosphoglycolate phosphatase pI isoelectric point RT-PCR reverse transcription-polymerase chain reaction Rubisco ribulose 1,5-bisphosphate carboxylase/oxygenase SGAT serine:glyoxylate aminotransferase SHMT serine hydroxymethyltransferase TAP tris acetate phosphate THF tetrahydrofolate WT wild-type x ABSTRACT The regulation of the photorespiratory pathway of Chlamydomonas reinhardtii during a shift from high to low CO 2 conditions was investigated. To this end, a set of C. reinhardtii cDNA sequences for known photorespiratory enzymes was assembled using the C. reinhardtii EST data and primary sequencing data. The cDNA sequences of the proposed photorespiratory genes are presented. A subset of these genes was used for expression analyses under varied conditions. Expression data indicates that there was a rapid and coordinated induction of photorespiratory and carbon dioxide concentrating mechanism (CCM) gene expression during a time course switch from elevated CO 2 conditions (5% [v/v]) to low CO 2 conditions (0.038% [v/v]). While the expression of photorespiratory and CCM genes was coordinated during the initial change in CO 2 level, the response of these two sets of genes to the CO 2 level was not identical. Unlike the …