Project description:Variations in Gastrolith disk and hypodermis transcript expression paterrns related to induced molt cycle were identified in male Cherax quadricarinatus using a cDNA microarray estimated to contain 2180 unique sequences. Molt induction was performed by repeated alpha-ecdysone injections. Manipulated males were sacrificed at late premolt and reference populations included intact intermolt and sham-injected intermolt individuals. Isolated gastrolith disk and hypodermis cDNAs of premolted male crayfish were hybridized onto the microarray against the sham-injected male reference. A putative effect of the injection procedure was also tested by hybridizing gastrolith disks cDNAs of sham-injected males vs. intact intermolt males. Differentially-expressed genes were identified, sequenced, and annotated. The sham injections had almost no effect on the gene expression patterns. The late premolt stage was characterized by a dramatic up-regulation of the genes in the gastrolith disk and milder but definite down-regulation in the hypodermis. The induced gastrolith genes included structural genes of the gastrolith and genes related to protein synthesis, energy provision and cell proliferation. Many other genes revealed no resemblance to known protein or nucleotide sequences, and their functions are yet to be uncovered. It is hypothesized that some of these genes are related to the calcium carbonate transportation and gastrolith deposition machinery.
