Functional and physical interactions between mammalian achaete-scute homolog 1 and myocyte enhancer factor 2A.

The mammalian achaete-scute homolog 1 (MASH1) protein is required for the early development of the nervous system. However, the molecular and biochemical mechanism by which MASH1 acts to determine neurogenesis are still unknown. The myocyte enhancer factor 2A (MEF2A) is a MADS transcription factor that is essential for the specification and differentiation of the muscle lineage. Here we show that MEF2A and MASH1 are coordinately induced during the differentiation of the teratocarcinoma cell line P19 along a neuronal lineage and that in transient transfection assays, MEF2A and MASH1 cooperatively activate gene expression. This cooperativity appears to be due to a specific physical interaction between MEF2A and MASH1. Taken together, these findings suggest that MASH1 via a cooperative interaction with MEF2A may regulate the expression of specific genes that are critical for neuronal differentiation.