Delayed fusion and altered gene expression contribute to semicircular canal defects in Chd7 deficient mice.
Proper morphogenesis of inner ear semicircular canals requires precise regulation of cellular proliferation, epithelial-to-mesenchymal transition, and fusion of epithelial plates. Epigenetic regulation of these processes is not well understood, but is likely to involve chromatin remodeling enzymes. CHD7 is a chromodomain-containing, ATP dependent helicase protein that is highly expressed in the developing ear and is required for semicircular canal development in both humans and mice. Here we report that mice with heterozygous loss of Chd7 function exhibit delayed semicircular canal genesis, delayed Netrin1 expression and disrupted expression of genes that are critical for semicircular canal formation (Bmp2, Bmp4, Msx1 and Fgf10). Complete loss of Chd7 results in aplasia of the semicircular canals and sensory vestibular organs, with reduced or absent expression of Otx1, Hmx3, Jagged1, Lmo4, Msx1 and Sox2. Our results suggest that Chd7 may have critical selector gene functions during inner ear morphogenesis. Detailed analysis of the epigenetic modifications underlying these gene expression changes should provide insights into semicircular canal development and help in the design of therapies for individuals with inner ear malformations.
Department of Pediatrics, The University of Michigan, Ann Arbor, MI 48109, USA.
Elizabeth A
EA
Hurd
Joseph A
JA
Micucci
Elyse N
EN
Reamer
Donna M
DM
Martin
D000818:Animals; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D044127:Epigenesis, Genetic; D004848:Epithelium / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006579:Heterozygote; D008648:Mesoderm / Q000254:growth & development / Q000378:metabolism; D051379:Mice; D009024:Morphogenesis / Q000235:genetics; D009154:Mutation; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D000075388:Netrin-1; D012665:Semicircular Canals / Q000002:abnormalities* / Q000254:growth & development / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
C507367:Chd7 protein, mouse; D004268:DNA-Binding Proteins; C000617351:NTN1 protein, human; D009414:Nerve Growth Factors; D025521:Tumor Suppressor Proteins; D000075388:Netrin-1