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Mouse myotomes pairs exhibit left–right asymmetric expression of MLC3F and α‐ skeletal actin
Author(s) -
Golding Jon P.,
Partridge Terence A.,
Beauchamp Jonathan R.,
King Tim,
Brown Nigel A.,
Gassmann Martin,
Zammit Peter S.
Publication year - 2004
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.20176
Subject(s) - biology , myotome , gastrulation , myogenesis , myosin , somite , anatomy , lateral plate mesoderm , pitx2 , actin , skeletal muscle , microbiology and biotechnology , nodal , embryo , mesoderm , embryogenesis , embryonic stem cell , genetics , gene expression , gene , homeobox
Most muscle originates from the myotomal compartment of the somites, paired structures flanking the neural tube. Whereas vertebrate embryos show molecular and morphological asymmetry about the left–right body axis, somitic myogenesis is thought to occur symmetrically. Here, we provide the first evidence that myotome pairs are transiently left–right asymmetric, with higher expression of α‐ skeletal actin and myosin light chain 3F ( MLC3F ) on the left side between embryonic day 9.5–10.25. In iv mutants with situs inversus , the asymmetric expression of α‐ skeletal actin and MLC3F was inverted, showing that this process is regulated by global left–right axis cues, initiated before gastrulation. However, although left–sided identity is later maintained by Pitx2 genes, we found that Pitx2c null embryos have normal left‐biased expression of α‐ skeletal actin and MLC3F . Myotome asymmetry, therefore, is downstream of the iv mutation but upstream of, or unrelated to, the Pitx2c pathway. Developmental Dynamics 231:795–800, 2004. © 2004 Wiley‐Liss, Inc.