MESP1

MESP1, or mesoderm posterior 1, is a transcription factor in the basic helix-loop-helix family encoded by the MESP1 gene in humans. It is expressed transiently in the early mesoderm during gastrulation and marks a population of multipotent cardiovascular progenitors. MESP1 is considered a master regulator of the cardiovascular lineage, initiating gene regulatory networks that steer cells toward cardiac, endothelial, and smooth muscle fates.

Functional studies in vertebrates and pluripotent stem cells indicate that MESP1 acts upstream of several cardiac transcription factors, including NKX2-5 and GATA4, and can drive differentiation toward cardiac progenitors when overexpressed in embryonic stem cells. Conversely, loss or reduction of MESP1 function in model organisms leads to defects in heart and vasculature formation, underscoring its essential role in early cardiogenesis.

Beyond its developmental role, MESP1 is studied in regenerative medicine as a potential driver for generating cardiovascular cells from pluripotent cells. Its expression patterns and regulatory interactions are part of broader gene networks that control mesoderm specification and lineage commitment during early development.

The MESP1 protein contains a basic helix-loop-helix domain that mediates DNA binding and dimerization, enabling it to regulate target genes in concert with other transcription factors. In research contexts, MESP1 serves as a molecular marker for cardiovascular progenitors and as a tool to study the early steps of heart and blood vessel formation.