title: Isl1 and Ldb co-regulators of transcription are essential early determinants of mouse limb development.
abstract: BACKGROUND
  The developing limb has served as an excellent model for studying pattern formation and signal transduction in mammalians. Many of the crucial genes that regulate growth and patterning of the limb following limb bud formation are now well known. However, details regarding the control of limb initiation and early stages of outgrowth remain to be defined. This report is focused on genetic events that pave the way for the establishment of a hindlimb bud.
  
  
  RESULTS
  Fgf10 and Tbx are crucial for early phases of limb bud initiation. Here we show that in the absence of Isl1 or of Ldb1/2, there is no hindlimb bud development. Fgf10 expression in the bud mesenchyme is dependent on Isl1 and its Ldb co-regulators.
  
  
  CONCLUSIONS
  Thus, Isl1 and the Ldb co-regulators of transcription are essential early determinants of mouse limb development. Isl1/Ldb complexes regulate Fgf10 to orchestrate the earliest stages of hindlimb formation.
authors.affiliation: Laboratory of Mammalian Genes and Development, Program in Genomics of Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA. ginatnarkis@gmail.com
authors.forename: Ginat
authors.initials: G
authors.lastname: Narkis
authors.forename: Itai
authors.initials: I
authors.lastname: Tzchori
authors.forename: Tsadok
authors.initials: T
authors.lastname: Cohen
authors.forename: Alex
authors.initials: A
authors.lastname: Holtz
authors.forename: Eric
authors.initials: E
authors.lastname: Wier
authors.forename: Heiner
authors.initials: H
authors.lastname: Westphal
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics*; D051526:Fibroblast Growth Factor 10 / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D006614:Hindlimb / Q000196:embryology*; D060588:LIM Domain Proteins / Q000235:genetics*; D060850:LIM-Homeodomain Proteins / Q000235:genetics*; D018878:Limb Buds / Q000196:embryology* / Q000502:physiology; D051379:Mice; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; C496464:Fgf10 protein, mouse; D051526:Fibroblast Growth Factor 10; D060588:LIM Domain Proteins; D060850:LIM-Homeodomain Proteins; C102084:Ldb1 protein, mouse; C106649:Ldb2 protein, mouse; D014157:Transcription Factors; C063843:insulin gene enhancer binding protein Isl-1