title: EBF proteins participate in transcriptional regulation of Xenopus muscle development.
abstract: EBF proteins have diverse functions in the development of multiple lineages, including neurons, B cells and adipocytes. During Drosophila muscle development EBF proteins are expressed in muscle progenitors and are required for muscle cell differentiation, but there is no known function of EBF proteins in vertebrate muscle development. In this study, we examine the expression of ebf genes in Xenopus muscle tissue and show that EBF activity is necessary for aspects of Xenopus skeletal muscle development, including somite organization, migration of hypaxial muscle anlagen toward the ventral abdomen, and development of jaw muscle. From a microarray screen, we have identified multiple candidate targets of EBF activity with known roles in muscle development. The candidate targets we have verified are MYOD, MYF5, M-Cadherin and SEB-4. In vivo overexpression of the ebf2 and ebf3 genes leads to ectopic expression of these candidate targets, and knockdown of EBF activity causes downregulation of the endogenous expression of the candidate targets. Furthermore, we found that MYOD and MYF5 are likely to be direct targets. Finally we show that MYOD can upregulate the expression of ebf genes, indicating the presence of a positive feedback loop between EBF and MYOD that we find to be important for maintenance of MYOD expression in Xenopus. These results suggest that EBF activity is important for both stabilizing commitment and driving aspects of differentiation in Xenopus muscle cells.
authors.affiliation: Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA. yangsook@neuro.utah.edu
authors.forename: Yangsook Song
authors.initials: YS
authors.lastname: Green
authors.forename: Monica L
authors.initials: ML
authors.lastname: Vetter
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D017403:In Situ Hybridization; D046228:Microarray Analysis; D024510:Muscle Development / Q000502:physiology*; D018482:Muscle, Skeletal / Q000196:embryology*; D017570:MyoD Protein / Q000378:metabolism; D051787:Myogenic Regulatory Factor 5 / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D015820:Cadherins; D017570:MyoD Protein; D051787:Myogenic Regulatory Factor 5; D016601:RNA-Binding Proteins; D029867:Xenopus Proteins; C497419:Myf5 protein, Xenopus; C414096:RBM24 protein, Xenopus; C489924:ebf2 protein, Xenopus; C070896:M-cadherin