Asynchronous activation of 10 muscle-specific protein (MSP) genes during zebrafish somitogenesis

作者：Xu YF; He JY; Wang XK; Lim TM; Gong ZY^*

来源：Developmental Dynamics, 2000, 219(2): 201-215.

DOI：10.1002/1097-0177(2000)9999:9999<::AID-DVDY1043>3.3.CO;2-9

• actin
• tropomyosin
• troponin
• myosin heavy chain
• myosin light chain
• creatine kinase
• parvalbumin
• desmin
• MyoD
• skeletal muscle
• cranial muscle
• cardiac muscle

In the present study, 10 zebrafish cDNA clones coding for muscle-specific proteins (MSPs) were characterized and most of them encode fast skeletal muscle isoforms. They are skeletal muscle alpha-actin (acta1), fast skeletal muscle atropomyosin (tpma), fast skeletal muscle troponin C (tnnc), fast skeletal muscle troponin T (tnnt), fast skeletal muscle myosin heavy chain (myhz1), fast skeletal muscle myosin light chain 2 (mylz2), fast skeletal muscle myosin light chain 3 (mylz3), muscle creatine kinase (ckm), parvalbumin (pvalb), and desmin (desm). Using these cDNA probes, their expression patterns in developing embryos and adults were compared by Northern blot hybridization and whole-mount in situ hybridization. All of the 10 genes are expressed in both embryos and adult fish, and the expression is highly abundant in skeletal muscle. Among them, acta1, tpma, tnnc, tnnt, myhz1, mylz2, mylz3 and pvalb, are expressed specifically in fast skeletal muscle while ckm and desm are expressed in both fast and slow skeletal muscles. In addition, tpma, ckm, and desm are also expressed in the heart. Ontogenetically, the onset of expression of these MSP genes in zebrafish skeletal muscle varies and the expression occurs rostral-caudally in developing somites. Shortly after the expression of myoD, desm is the first to be activated at similar to 9 hpf, followed by tpma (similar to 10 hpf), tnnc (similar to 12 hpf), acta1 (similar to 12 hpf), ckm (similar to 14 hpf), myhz1 (similar to 14 hpf), mylz2 (similar to 16 hpf), mylz3 (similar to 16.5 hpf), tnnt (similar to 16.5 hpf), and pvalb (similar to 16.5 hpf). At later stages (after 48 hpf), these MSP genes are also expressed in fin buds and head muscles including eye, jaw, and gill muscles. Thus, our experiment demonstrated the order of expression of the 10 MSP genes, which may reflect the sequence of muscle filament assembly. In spite of the asynchrony in activation of these MSP genes, the timing of expression for each individual MSP gene appears to be synchronous to somite development as each somite has an identical timetable to express the set of MSP genes.

• 出版日期2000-10