The Genomic Sequence Clone, Bioinformatics And Express Analysis Of Cbr In Dunaliella Salina

Early light-induced protein (ELIP) is positively light-regulated gene found at the beginning of the 1980s. When the higher plant are under the high light will cause the photooxidation, light efficiency decrease, photoproduct lower. The ELIP will be induced quickly to clear up this harmful effect. Dunaliella salina is the most extreme halotolerat alga in the world, most distribute in some salt fields and oceans. Dunaliella salina can live in the extreme environments, the research mainly focus on its salt tolerance and high light tolerance. There are a lot of papers on its moleculal mechanism of salt tolerance, but little on its high-light tolerance. We report here that we cloned the full genomic DNA length of the cDNA sequence in Dunaliella salina by PCR method and found it have three exon, the same as in other ELIP, the GC ration is much higher in exon than that in intron. Then we use bioinformatics tools analyzing this cDNA. The result suggest it was high homologous to the Cbr in D.bardwail. Though motif search, chlorophyll binding analyze indicated it belong to chlorophyll a/b-binding protein (Cab) family. The second structure prediction and transmembrance prediction suggest its has three a-helix, helix- I and helix-III are conserve. It has the Glul and Asn4 in helix- I and Glu69 and Asn72 in helix-III chlorophyll bind site. Then homology model the three structure of this sequence with a cab as template which has 42% homology to it, the two sites are close in the space, they are proposed to be chlorophyll bind sites. Finally we treat the D.salinawith high salt shock, low salt shock and high-light stress, the results of Northern blotting indicated that this gene is accumulated in the first two hours of treat then degraded. Using spectrophotometer mensurate the ratio between the chlorophyll(a) and carotenoids, and we found the ratio is decrease when Dunaliella is under the stress.All the results are in accord with the ELIP, so we finally identify this cDNA sequence is Cbr gene. This is not only important to explain the development of photosystem in Dunaliella but also help us to understand the signal transfer pathway when Dunaliella in various extremity environments.