Molecular characterization of an epithelial Ca2+ channel-like gene from crayfish Procambarus clarkii.
This study describes the cloning, sequencing and functional characterization of an epithelial Ca(2+) channel (ECaC)-like gene isolated from antennal gland (kidney) of the freshwater crayfish Procambarus clarkii. The full-length cDNA consisted of 2687 bp with an open reading frame of 2169 bp encoding a protein of 722 amino acids with a predicted molecular mass of 81.7 kDa. Crayfish ECaC had 76-78% identity at the mRNA level (80-82% amino acid identity) with published fish sequences and 56-62% identity at the mRNA level (52-60% amino acid identity) with mammalian ECaCs. Secondary structure of the crayfish ECaC closely resembled that of cloned ECaCs. Postmolt ECaC expression was exclusively restricted to epithelia associated with Ca(2+) influx and was virtually undetectable in non-epithelial tissues (eggs, muscle). Compared with expression levels in hepatopancreas, expression in gill was 10-fold greater and expression was highest in antennal gland (15-fold greater than in hepatopancreas). Compared with baseline expression levels in intermolt stage, expression of ECaC in antennal gland increased 7.4- and 23.8-fold, respectively, in pre- and postmolt stages of the molting cycle. This increase was localized primarily in the labyrinth and nephridial canal, regions of the antennal gland associated with renal Ca(2+) reabsorption. The ECaC in crayfish appears to be expressed in epithelia associated with unidirectional Ca(2+) influx and relative expression is correlated with rate of Ca(2+) influx.
Gao
Yongping
Y
Department of Biological Sciences, Wright State University, Dayton, OH 45435, USA.
Wheatly
Michele G
MG
D000595:Amino Acid Sequence; D000818:Animals; D003400:Astacoidea / Q000235:genetics*; D001483:Base Sequence; D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism; D016000:Cluster Analysis; D017931:DNA Primers; D004847:Epithelial Cells / Q000737:chemistry*; D005880:Gills / Q000378:metabolism; D043143:Hepatopancreas / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
D015220:Calcium Channels; D017931:DNA Primers