Microarray-detected changes in gene expression in gills of green crabs (Carcinus maenas) upon dilution of environmental salinity.

The interaction between environmental salinity and gene expression was studied in gills of the euryhaline green shore crab Carcinus maenas. A 4462-feature oligonucleotide microarray was used to analyze changes in transcript abundance in posterior ion-transporting gills at 8 time periods following transfer of animals from 32 to 10 or 15 ppt salinity. Transcripts encoding Na(+)/K(+)-ATPase α-subunit and cytoplasmic carbonic anhydrase were upregulated with significant changes between 6 and 24h post-transfer. Other transport proteins showing similar transcriptional upregulation were an organic cation transporter, a sodium/glucose cotransporter, an endomembrane protein associated with regulating plasma membrane protein composition, and a voltage-gated calcium channel. Transport proteins showing little transcriptional response included Na(+)/H(+) exchanger, Na(+)/K(+)/2Cl(-) cotransporter, and V-type H(+)-ATPase B subunit, all of which have been implicated in osmoregulatory ion transport across crustacean gill. Interestingly, there was little affect of salinity dilution on transcriptional expression of stress proteins, suggesting that salinity acclimation is part of normal physiology for C. maenas. Expression of transcripts encoding a variety of mitochondrial proteins was significantly upregulated between 4 days and 7 days post-transfer, consistent with the proliferation of mitochondria-rich cells previously observed at this time.