LOCALIZED EXPRESSION OF A MYOGENIC REGULATORY GENE, QMF1, IN THE SOMITE DERMATOME OF AVIAN EMBRYOS

qmf1 is a quail myogenic regulatory gene that is transcribed in skeletal myoblasts and differentiated muscle and shows sequence homology to MyoD1 and Myf5. We used the qmf1 transcript as an in situ hybridization marker for determined myogenic cells to study myogenic lineages in developing embryos. We present evidence for the temporal and spatial regulation of qmf1 mRNA expression and slow cardiac troponin C (TnC), fast skeletal troponin T (TnT), and α-cardiac actin contractile protein mRNA expression in the somite myotome and limb buds. Our results show that qmf1 is a marker for myogenic lineages during both somite formation and limb development and that qmf1 mRNAs, but not contractile protein mRNAs, localize in dorsal medial lip (DML) cells of the somite dermatome. We propose that the DML is a site of myogenic lineage determination.