Fig. 4

SMYD1b is co-regulated with other myosin chaperones HSP90a1 and UNC45b.

In-situ hybridization staining of wild type and still heart embryos shows that hsp90a1 expression is normal in still heart mutants, when compared to wild type embryos at 19hpf (A&B). However, the expression of hsp90a1 and unc45b dramatically increases in still heart mutants at 24hpf (C-F & K) and 48hpf throughout the somites (G-J & M). Additionally, smyd1b expression increases significantly when UNC45b is absent in steif mutants (N), supporting co-regulation of these three genes. (O) A time course of smyd1b expression during muscle formation reveals that smyd1b is expressed early at 10hpf when unc45b is expressed and increases in its expression as muscle development progresses. Due to the rapid development of unc45b staining in the somites of the embryo in panel J, the head while present, has no background staining and is not clear in this focal plane. (qPCR: n = 3, 30 embryos each time/phenotype. Error bars are standard deviation.).