Meeting Abstract

P2.141  Monday, Jan. 5  Effect of cold acclimation on the expression of sarcoplasmic calcium binding protein (pcSCP1) variants in the freshwater crayfish, Procambarus clarkii. WHITE, A.J.*; GILLEN, C.M.; NORTHCUTT, M.J.; GAO, Y.; WHEATLY, M.G.; Kenyon College, Gambier, OH; Kenyon College, Gambier, OH; Kenyon College, Gambier, OH; Wright State University, Dayton, OH; Wright State University, Dayton, OH gillenc@kenyon.edu

We have investigated the effect of cold exposure on sarcoplasmic calcium binding protein (pcSCP1) from the freshwater crayfish, Procambarus clarkii. pcSCP1 is an EF-hand calcium binding protein that is highly expressed in invertebrate muscles where it acts as a calcium buffer. Sequencing of full length pcSCP1 clones revealed three variants of pcSCP1 (pcSCP1a, pcSCP1b, and pcSCP1c) that are identical except for a variable region between base pairs 222 and 345 of the 579 base pair open reading frame. We assessed expression of pcSCP1 by real-time PCR with variant specific primers using the relative quantification method and 18s ribosomal RNA as an internal calibrator. Expression of all three variants was highest in axial muscle, more than 10,000 fold above hepatopancreas. pcSCP1c was the primary variant in cardiac muscle where it was expressed about 10 fold above hepatopancreas. To evaluate expression during cold acclimation, crayfish were kept at 4 degrees Celsius for 7 days and a control group was kept at room temperature. Heart pcSCP1 was found to be dramatically downregulated by cold exposure; all three variants were undetectable after cold exposure. In contrast, pcSCP1b and pcSCP1c were moderately upregulated (3 to 7 fold) in axial muscle after cold acclimation. (Funded by NSF 0445202 and Kenyon College).