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Regulation of a muscle‐specific transgene by persistent expression of hox genes in postnatal murine limb muscle
Author(s) -
Houghton Leslie,
Rosenthal Nadia
Publication year - 1999
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/(sici)1097-0177(199912)216:4/5<385::aid-dvdy7>3.0.co;2-g
Subject(s) - hox gene , biology , homeobox , enhancer , hindlimb , ectopic expression , transgene , limb bud , microbiology and biotechnology , gene , regulation of gene expression , homeobox a1 , mef2 , dlx5 , gene expression , reporter gene , genetics , anatomy
Homeobox genes are necessary for the generation of the embryonic body plan in both invertebrate and vertebrate organisms. To investigate the potential function of homeodomain proteins in normal and regenerating skeletal muscle, we analyzed patterns of clustered homeobox gene expression in neonatal and adult muscle tissue. Transcripts encoding 5′ genes in the HoxA cluster were detected in muscles from both the fore‐ and hindlimbs of neonatal and adult mice, whereas expression of HoxC gene transcripts was generally restricted to the muscles of the hindlimb. In contrast, transcripts encoding genes of the HoxB or HoxD clusters were not detected in muscles from either fore‐ or hindlimbs. Although ectopic expression of select HOX proteins in muscle cell cultures had modest effects upon the activity of a co‐transfected myosin light chain (MLC) enhancer, mutation of a Hox binding site in this enhancer elicited increased linked reporter gene expression. Induction of muscle damage and regeneration was accompanied by the down‐regulation of at least one Hox gene, concurrent with the activation of the regenerative program. Moreover, targeted ablation of the Hoxc‐8 gene, normally expressed in mature fore‐ and hindlimb muscles, resulted in reduced expression of an MLC enhancer‐driven transgene only in specific leg muscles. These results indicate that members of the HoxA and C clusters may, in combination, mediate various aspects of differentiation and patterning in adult musculature. Dev Dyn 1999;216:385–397. ©1999 Wiley‐Liss, Inc.