CLONING,SEQUENCING AND DETERMINATION OF THE GENE FRAGMENT OF α-CHAIN OF ATP SYNTHASE IN DUNALIELLA BARDAWIL

Halophilic alga Dunaliella bardawil (Chlorophyceae) was cultivated in artificialseawater (containing 3 .0, 1. 5 or 0. 5 mol/L of NaCl respectively) for at least two weeks; total RNAswere then extracted and 8 stable differential bands were harvested after DDRT-PCR and electrophoresis.The retrieved bands were amplified, subjected to electrophoresis again, and cloned into plasmid pUCm-Trespectively. After exelusion of false positive bands, We obtained a recombinant plasmid pTE containing afragment of cDNA, which was only specilically expressed under high salinity condition. Sequencing of

Halophilic alga Dunaliella barduwil (Chlorophyceae) was cultivated in artificial seawater (containing 3.0, 1 .5 or 0.5 mol/L of NaCI respectively) for at least two weeks; total RNAs were then extracted and 8 stable differential bands were harvested after DDRT-PCR and electrophoresis. The retrieved bands were amplified, subjected to electrophoresis again. and cloned into plasmid pUCm-T respectively . After exclusion of false positive bands, We obtained a recombinant plasmid pTE containing a fragment of cDNA, which was only specifically expressed under high salinity condition. Sequencing of the cDNA showed that it was 424 bp. According to the results of homologous comparison of the nucleotide and putatived amino acid sequence with known sequence and search for the polypeptide conserved domain, it was considered that this specific band could be a gene fragment coding for the a-chain of proton transporting ATP synthase (H + transporting two-sector ATPase) in the chloroplast of D . bardawil, which is regulated by high salinity.