title: Establishment and characterization of immortalized Gli-null mouse embryonic fibroblast cell lines.
abstract: BACKGROUND
  Hedgehog (Hh) signaling is a conserved morphogenetic pathway which plays critical roles in embryonic development, with emerging evidence also supporting a role in healing and repair processes and tumorigenesis. The Gli family of transcription factors (Gli1, 2 and 3) mediate the Hedgehog morphogenetic signal by regulating the expression of downstream target genes. We previously characterized the individual and cooperative roles of the Gli proteins in Hh target gene regulation using a battery of primary embryonic fibroblasts from Gli null mice.
  
  
  RESULTS
  Here, we describe the establishment of spontaneously immortalized mouse embryonic fibroblast (iMEF) cell lines lacking single and multiple Gli genes. These non-clonal cell lines recapitulate the unique ligand mediated transcriptional response of primary MEFs. While loss of Gli1 had no effect on target gene induction, Gli2 null cells demonstrated reduced target gene induction while Gli3 null cells exhibited elevated basal and ligand-induced expression. Target gene response in Gli1-/-2-/-iMEFs was severely reduced while Gli2-/-3-/-iMEFs were incapable of ligand-induced transcriptional response. However, we found that both Gli1-/-2-/- and Gli2-/-3-/-iMEFs exhibited robust leukotriene synthesis-dependent migration responses to Hh ligand, demonstrating that this response is not transcriptionally-dependent.
  
  
  CONCLUSIONS
  This study provides fundamental characterizations of the transcriptional and non-transcriptional Hh responsiveness of a battery of Gli-null iMEFs. Moving forward, these cell lines should prove a valuable tool set to study the unique functional regulation of the Gli proteins in a Hh-responsive cell-type.
authors.affiliation: Department of Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA. lipinski@surgery.wisc.edu
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lipinski
authors.forename: Maarten F
authors.initials: MF
authors.lastname: Bijlsma
authors.forename: Jerry J
authors.initials: JJ
authors.lastname: Gipp
authors.forename: David J
authors.initials: DJ
authors.lastname: Podhaizer
authors.forename: Wade
authors.initials: W
authors.lastname: Bushman
mesh_terms: D000818:Animals; D002460:Cell Line; D004622:Embryo, Mammalian / Q000166:cytology*; D005347:Fibroblasts / Q000166:cytology*; D053823:Hedgehog Proteins / Q000235:genetics / Q000378:metabolism; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D015398:Signal Transduction; D014158:Transcription, Genetic; D000071676:Zinc Finger Protein GLI1
chemical_list: C498520:Gli1 protein, mouse; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D000071676:Zinc Finger Protein GLI1
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