Tg(mylpfa:H2B-GFP) transgene and its expression. A: Schematic diagram of the Tg(mylpfa:H2B-GFP) construct used to generate the transgenic lines. 1.934 kb of mylpfa promoter region is placed upstream of H2B-GFP cDNA. B-E: Anti-GFP staining of transgenic embryos at different stages. Tg(mylpfa:H2B-GFP) expression is detected in the anterior somites by 1 d.p.f. (B), and is present throughout the trunk by 2 d.p.f. (C). Tg(mylpfa:H2B-GFP) expression in various cranial skeletal muscles in a 3 d.p.f. embryo. The muscles are labeled according to ( Schilling and Kimmel, 1997): am, adductor mandibulae; hh, hyohyoideus; ih, interhyoideus; ima, intermandibularis anterior; imp, intermandibularis posterior; sh, sternohyoideus (D). Transgene expression in the pectoral fin muscles (indicated by arrows) in a 5 d.p.f. embryo (E). F: Fast-twitch and slow-twitch muscle cells in 2 d.p.f. transgenic embryos. Anti-GFP staining of transgene colocalized with DAPI staining of nuclei in fast-twitch muscle cells labeled with F310 antibody (top panel), whereas in slow-twitch muscle cells labeled with F59 antibody, there is little specific anti-GFP staining and no colocalization with nuclei labeled with DAPI (bottom panel). Scale bar = 50 µm.

Tg(mylpfa:H2B-GFP) expression in jam3bsa37 mutants. A: Tg(mylpfa:H2B-GFP) chevron-shaped expression pattern in the jam3bsa37 mutant (indicated with an asterisk) allows easy identification from its non-mutant siblings under a fluorescence stereomicroscope. B: Fast-twitch muscle cells of 2 d.p.f. transgenic embryo displaying Tg(mylpfa:H2B-GFP) chevron-shaped expression pattern are mostly mononucleated, thus confirming its identity as a jam3bsa37 mutant. Fast-twitch muscle cells are labeled with F310 antibody, with the nuclei and cell membranes stained with anti-GFP and anti-β-catenin respectively. Scale bar = 50 µm.

Acknowledgments
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Reprinted from Gene expression patterns : GEP, 20(2), Zhang, W., Roy, S., The zebrafish fast myosin light chain mylpfa:H2B-GFP transgene is a useful tool for in vivo imaging of myocyte fusion in the vertebrate embryo, 106-10, Copyright (2016) with permission from Elsevier. Full text @ Gene Expr. Patterns