Identification of differentially expressed genes during the brachyurization of the Chinese mitten crab Eriocheir japonica sinensis.

Expressed sequence tags (ESTs) obtained from two-directional suppression subtractive hybridization (SSH) of cDNA libraries derived from the pleon of the Chinese mitten crab were analyzed using mRNA subtractive hybridization. After cDNA cloning and sequencing, gene expression profiles were examined, focusing on brachyurization. We assembled 211 non-redundant ESTs from SSH library 1 (yielding 130 unique transcripts: 25 consensi, 105 singletons) and 669 from SSH library 2 (195: 51 consensi, 144 singletons). Functional analysis shows that these genes are putatively involved in various cellular processes (33%), ribosomal RNA/proteins (30%), molting (12%), signal transduction (6%), immune factor and stress proteins (6%), development (4%), energy metabolism (3%), and mitochondrial membrane protein, hormone metabolizing, and chaperone (1% each) of other organisms. Some 3% are of unknown function in SSH library 1. The results facilitate the functional study of candidate genes involved in early developmental processes, especially the regulation of brachyurization in this crab.