Lg. Robson et Sm. Hughes, Local signals in the chick limb bud can override myoblast lineage commitment: induction of slow myosin heavy chain in fast myoblasts, MECH DEVEL, 85(1-2), 1999, pp. 59-71
Patterning of fast and slow muscle fibres in limbs is regulated by signals
from non-muscle cells. Myoblast lineage has, however, also been implicated
in fibre type patterning. Here we test a founder cell hypothesis for the ro
le of myoblast lineage, by implanting characterized fast and slow mouse myo
blast clones into chick limb buds. In culture, late foetal mouse myoblast c
lones are committed to a probability (range 0-0.92) of slow myosin heavy ch
ain (MyHC) expression. In contrast, when implanted into chick limbs, fast m
ouse myoblast clones express myosin characteristic of their new environment
, without fusion to chick muscle cells and in the absence of innervation. T
herefore, local signals exist within the chick limb bud during primary myog
enesis that can override intrinsic commitment of at least some myoblasts, a
nd induce slow MyHC. (C) 1999 Elsevier Science Ireland Ltd. All rights rese
rved.