Meeting Abstract

P2.85  Tuesday, Jan. 5  Analysis of sarcoplasmic calcium binding protein in Procambarus clarkii muscle GILLEN, C.M.*; WHITE, A.J.; CARPENTER, R.O.; ROHRBACK, S.E.; GAO, Y.; WHEATLY, M.G.; Kenyon College; Kenyon College; Kenyon College; Kenyon College; Wright State University; Wright State University gillenc@kenyon.edu

SCP1 is an invertebrate EF-hand calcium binding protein that is hypothesized to serve a function similar to vertebrate parvalbumin, which is expressed most highly in fast-twitch muscle fibers. We have identified three variants of the Procambarus clarkii sarcoplasmic calcium binding protein (pcSCP1a, pcSCP1b, pcSCP1c). In this study, we used relative quantification real-time PCR to evaluate the expression of pcSCP1, using variant-specific primers and 18s ribosomal RNA as an internal calibrator. All three variants are highly expressed in axial abdominal muscle and are also detectable in cardiac muscle. Expression of the three variants was 10-100 fold higher in deep flexor (fast, phasic) compared to superficial flexor (slow, tonic) muscles. To probe the function of pcSCP1, we injected double-stranded RNA to reduce pcSCP1 expression, resulting in an average 2-fold reduction of pcSCP1 expression compared to controls, with up to 10-fold reduction in individual crayfish. Crayfish with reduced pcSCP1 expression showed muscular weakness compared to controls, based on visual inspection. These findings are consistent with pcSCP1 playing a similar role to vertebrate parvalbumin. (Funded by NSF-IBN 0445202 and Kenyon College)