Chaya Kalcheim: "Mechanisms of early muscle development"

Chaya Kalcheim

Dept. of Medical Neurobiology- Hebrew University of Jerusalem- IMRIC and ELSC- Jerusalem, Israel

Mechanisms of early muscle development

The development of a functional tissue requires coordination between the amplification of progenitors and their differentiation into specific cell types.
To tackle this question, I will focus my talk on the development of the early embryonic muscle, the myotome. The molecular basis for this coordination during myotome ontogeny is not well understood. The myotome mostly derives from an embryonic epithelium termed the “dermomyotome”. The latter is a heterogeneous structure composed of both multipotent as well as of fate-restricted progenitors giving rise to striated and smooth muscle, mitotic muscle progenitors, and also to dorsal dermis and endothelium of adjacent blood vessels.
We showed that the segregation into these lineages occurs in a spatially and temporally-regulated fashion. I will illustrate the impact of cell-intrinsic mechanisms (oriented cell divisions) and of environmental factors (i.e; Sonic hedgehog) on the above processes. Our results demonstrate a pivotal role for LGN-dependent oriented mitoses in the choice of dermomyotome-derived fates, as well as the significance of a transient dynamics of Sonic hedgehog signaling in muscle differentiation and in its transition from a specification into a growth phase.