title: HnRNP U mediates the long-range regulation of Shh expression during limb development.
abstract: Transcriptional modulation may be mediated by cis-regulatory elements distant from their target genes. Mutations in a conserved locus about 1 Mb upstream of the Shh coding region often affect Shh expression and are associated with preaxial polydactyly (PPD) defects. To understand the molecular mechanism, we analyzed a novel mouse PPD model with a T-to-A point mutation in this distant locus. A core element of mutation (CEM) with putative enhancer activity was identified by promoter activity assay and shown to contain a matrix attachment region. HnRNP U preferentially bound to the mutant but not the wild-type CEM. Interestingly, HnRNP U also bound to the 5'-UTR of the Shh gene, which was not located in the nuclear matrix in wild-type embryonic cells, as indicated by chromatin immunoprecipitation. We propose that the 5'-UTR of Shh was pulled into the nuclear matrix by HnRNP U when the CEM was mutated, and consequently affected Shh expression. Therefore, distant cis-elements may modulate gene expression by altering HnRNP U's affinity for certain mediator proteins and nuclear relocation.
authors.affiliation: MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Medical School of Nanjing University, 12 Xuefu Road, Pukou District, Nanjing 210063, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Ding
authors.forename: Yingqian
authors.initials: Y
authors.lastname: Li
authors.forename: Kaiqun
authors.initials: K
authors.lastname: Ren
authors.forename: Jiahao
authors.initials: J
authors.lastname: Sha
authors.forename: Minsheng
authors.initials: M
authors.lastname: Zhu
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
mesh_terms: D000818:Animals; D005121:Extremities / Q000196:embryology*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins / Q000235:genetics* / Q000378:metabolism; D034722:Heterogeneous-Nuclear Ribonucleoprotein U / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D015530:Nuclear Matrix / Q000235:genetics / Q000378:metabolism; D017354:Point Mutation; D017689:Polydactyly / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport
chemical_list: D053823:Hedgehog Proteins; D034722:Heterogeneous-Nuclear Ribonucleoprotein U; C465570:Shh protein, mouse