Meeting Abstract
Crustaceans progress through the intermolt, premolt, and postmolt stages during the molt process to shed their old exoskeleton and grow. The Y-organ (YO) controls molting processes through the synthesis of molting hormones (ecdysteroids). Environmental stress inhibits molting by repressing ecdysteroids by the YO. The purpose of the study is to identify and characterize mRNA sequences encoding stress-response genes in a de novo-assembled transcriptome of the YO of the blackback land crab, Gecarcinus lateralis. Here we report the identification and expression of Sirtuin genes to understand how external and internal stressors may inhibit molting. Sirtuin family includes seven orthologs (Sirt1 – Sirt7) distributed in four classes regulating important biological pathways in bacteria and eukaryotes. Sirtuins deacetylase target substrates on nicotinamide adenine dinucleotide (NAD+) availability as a cofactor. Their function has been associated with caloric restriction, energy metabolism, and stress resistance. In stress occurrence, Sirtuins promote resistance and cell survival through suppression of genes and pathways associated to specific transcription factors identified in mammals. Contigs encoding Sirtuins 1, 4, 5, and 7 were identified. Amino acid sequences shared some residues in the core region but differed in structure of N- and C- terminal domains. Differences in residues of the terminal regions describe characteristic biological properties of these proteins in three subcellular localizations. Relative expression of Sirtuins from intermolt to postmolt stage of G. lateralis exposed an important decrease in mean FPKM (p<0.05). The presence of Sirtuin sequences in the YO suggests that environmental stressors inhibit molting by acting directly on the YO. Supported by NSF (IOS-1257732).
