Mysm1^tm1a/tm1a mouse line–gene targeting and gross phenotypic characterization. (A) Structure of the Mysm1^{tm1a(KOMP)WTSI} (Mysm1^tm1a) allele. (B) Fold reduction in Mysm1-transcript in Mysm1^tm1a/tm1a relative to wild-type tissues (liver, spleen, thymus, skeletal muscle, brain, embryonic fibroblasts), analyzed by qRT-PCR using primers spanning the junction of exons 2 and 3 of Mysm1 transcript ENSMUST00000075872. Bars show means ± SEM. (C) Reduced weight of Mysm1^tm1a/tm1a mice. Bars show means ± SD; shaded area shows 95% reference range for all wild-type mice of the same strain and sex. Data are from males and are representative of the differences seen for both sexes. (D) Representative images showing reduced body size and dysmorphology in Mysm1^tm1a/tm1a mice, compared with a wild-type littermate control. (E) Numbers of significantly up-regulated and down-regulated genes in Mysm1^tm1a/tm1a versus wild-type control, by tissue and cell type, based on adjusted P ≤ .05 (tissue and fibroblast comparisons are between 3-4 mice per group; ES cell comparisons are between multiple independently passaged samples of wild-type JM8 line and a Mysm1^tm1a/tm1a ES cell line derived from mouse blastocysts).