Identifying Genes Associated with the Molecular Scleractinian Coral Calcification Process (Stylophora pistillata study case)

Increasing seawater’s calcium concentration has shown to increase reef building (scleractinian) coral’s calcification rates. In this way the expression of the genes that are associated with the calcification process also altered and, thus can be identified. Needless to say that the overall gene repertoire that participate in the coral calcification process and its molecular mechanisms have not yet been revealed, although sporadic genes that are related to the process have been discovered and investigated. In this study, nubbins of the Red Sea scleractinian coral, Stylophora pistillata were treated with increased calcium concentrations seawater (addition of 100 gm/L) and the genes that have been up-regulated were compared to the genes expression profile of corals with natural seawater calcium concentration. Measurements of AT were taken at mid-day (11:00) and in nighttime (23:00), to record the calcification rates of coral individuals under normal and increased calcium seawater concentrations. In order to reveal the gene involved in the calcification process, S. pistillata fragments of normal and of increased calcium concentrations were sampled for microarray RNA transcriptional profiling at two time-points (mid-day and nighttime).Results of this study have revealed that Smad genes may play a role in the coral skeletal growth apparatus. This study show that the calcification molecular mechanism is conserved Among identified genes are large group of genes that are characterized in the TGF-b/BMP signal transduction pathways which have been revealed in other organisms to participate in bone and cartilage tissue development molecular processes. 2-condition experiment: in two time points, mid-day (11:00) and night (23:00), coral fragments of S. pistillata were sampled after treated with seawater added with calcium concentration of 100mg/L (T11 and T23). In addition, control treatment for the two time points were sampled (C11 and C23), and free swimming larvae (plan). Data from three to five biological replicates were used (except the palnulla which have 1 replicate).