Molecular characterization of the sarcoplasmic calcium-binding protein (SCP) from crayfish Procambarus clarkii.
Sarcoplasmic Calcium-binding Protein (SCP) is believed to function as the invertebrate equivalent of vertebrate parvalbumin, namely to "buffer" cytosolic Ca2+. We have cloned and characterized a novel SCP from axial abdominal muscle of crayfish Procambarus clarkii (referred to as pcSCP1), and have examined tissue specific distribution and expression as a function of molting stage in non-epithelial and epithelial tissues. The complete sequence of pcSCP1 consists of 1,052 bp with a 579 bp open reading frame, coding for 193 amino acid residues (molecular mass of 21.8 kDa). There is a 387 bp 3' terminal non-coding region with a poly (A) tail. The deduced pcSCP1 protein sequence matched most closely with published SCP sequences from another crayfish Astacus leptodactylus (92.8%) and from shrimp (78.6-81.2%) and fruit fly (53%). Real-time PCR analysis confirmed that pcSCP1 is ubiquitously expressed in all tissues tested (gill, hepatopancreas, intestine, antennal gland, muscle); however it is most abundant in muscle particularly in the axial abdominal muscle. The real-time PCR analysis revealed that pcSCP1 expression is downregulated in pre- and postmolt stages compared with intermolt. Epithelial (hepatopancreas and antennal gland) SCP expression exhibited a more dramatic decrease than that observed in muscle. Expression trends for pcSCP1 paralleled published trends for sarco/endoplasmic reticular calcium ATPase (SERCA), suggesting that their cellular function in regulating intracellular Ca2+ is linked.
Gao
Yongping
Y
Department of Biological Sciences, Wright State University, Dayton, OH 45435, USA.
Gillen
Christopher M
CM
Wheatly
Michele G
MG
D000595:Amino Acid Sequence; D000818:Animals; D003400:Astacoidea / Q000378:metabolism*; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D018978:Molting; D009132:Muscles / Q000378:metabolism; D009928:Organ Specificity; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D012333:RNA, Messenger