Figure 2. Myosin heavy chain mRNA isoforms and β-actin cDNA from extraocular muscles

Extraocular muscles (EOMs) from postnatal day 0 expressed predominantly neonatal myosin heavy chain (MYHC-PN), with a lesser percentage of embyonic MHC (MYHC-Emb) and 2A MHC (MYH2A). In the 14-day-old rats, EOMs expressed all isoforms of MHC with a predominance of 2X MHC (MYH2X) and 2A MHC. In the adult rats, EOMs expressed approximately equal percentages of 2X MHC, 2A MHC, and 2B MHC (MYH2B). For competitive PCR, the initial concentration of the competitor was 1 fmol (lane 1) and 3 fold serial dilutions to 333 amoles (lane 2), 111 amoles (lane 3), 37 amoles (lane 4), 12.3 amoles (lane 5), 4.12 amoles (lane 6), 1.37 amoles (lane 7), 0.46 amoles (lane 8), 0.15 amoles (lane 9), and 0.05 amoles (lane 10). The upper bands of the PCR products are the targets and the lower bands are competitors. Arrowheads indicate the approximate concentration at which target and competitor are the same. In the first lane, the "L" is a 100 bp ladder with 600 bp indicated. The plus sign indicates a RT-PCR band of MHC mRNA transcripts without competitor. Gels are shown for 2A MHC, 2B MHC, 2X MHC, EOM MHC (MYHC-EO), embryonic MHC, neonatal MHC, β-cardiac MHC (MYHCB), and β-actin.