Figure 4.

Semi-quantitative PCR. We designed specific primers for 11 transcripts randomly selected among those isolated from the subtracted HM3/S³ library and measured the corresponding level of expression in skeletal muscle by semi-quantitative PCR amplification. The PCR reaction was stopped after the indicated number of cycles. Shown on the right is the EST ID of some selected transcripts. As controls we chose well characterized genes expressed at high or intermediate levels in striated muscle. GADP, glyceraldehyde 3-phosphate dehydrogenase, a popular standard in several cDNA expression panels; TELE, telethonin/titin cap, expressed at high level (Table S1); ANKRD2, ankyrin repeat domain 2 protein, intermediate abundance in our cDNA libraries (0.06%). For the last two genes the expression level in muscle was measured by a variety of other techniques in our laboratory (38,39).