Fig. 1: SAM is enriched in myoblast and promotes cell proliferation in vitro.

a Genomic snapshot of mouse SAM generated in RefSeq, RNA-seq, histone marks ChIP-seq from activated satellite cells (ASCs), MyoD ChIP-seq from C2C12 myoblasts. b Schematic illustration of the genomic location and structure of mouse SAM (Gm11974) locus. c Semi-quantitative RT-PCR detection of full-length SAM transcript (592 nt) in C2C12 myoblasts. d qRT-PCR analysis of SAM in mouse muscle vs. isolated primary myoblasts. e qRT-PCR detection of SAM in freshly isolated SCs (FISCs), activated SCs (ASCs), or differentiated SCs (DSCs) isolated from muscles of Tg: Pax7-nGFP mice. f FISH was performed in the above FISCs, ASCs, or DSCs. g qRT-PCR analysis of RNAs purified from cytoplasmic or nuclear fraction of ASCs. h qRT-PCR detection of SAM from ASCs transfected for 48 h with either control (siNC) or SAM siRNA (siSAM-1 or siSAM-2). i Immunofluorescence (IF) staining for Pax7 and MyoD or j Ki67 was performed in the above transfected cells and the percentage of positively stained cells was quantified. k qRT-PCR detection of SAM from ASCs transfected for 48 h with a Vector or SAM expressing plasmid. l IF staining for Pax7 and MyoD or m Ki67 was performed in the above transfected cells. n Single myofibers were isolated from EDL muscles of adult C57BL/6 mouse and transfected with siSAM oligos. IF staining of MyoD and MyoG was performed 72 h after transfection and the percentage of positively stained cells was quantified. The data are presented as mean ± SD in d, e, g–i and k. The center line in j, l, m, and n is presented as mean. The p values by two-tailed unpaired t test are indicated in d, e, h–n. The total number of biologically independent samples are indicated in d, e, g–n. Scale bars: 10 µm f, 100 µm i, j, l, m, and n. Source data are provided as a Source Data file.