title: Kit regulatory elements required for expression in developing hematopoietic and germ cell lineages.
abstract: The Kit (White) gene encodes the transmembrane receptor of stem cell factor/Kit ligand (KL) and is essential for the normal development/maintenance of pluripotent primordial germ cells (PGCs), hematopoietic stem cells (HSCs), melanoblasts, and some of their descendants. The molecular basis for the transcriptional regulation of Kit during development of these important cell types is unknown. We investigated Kit regulation in hematopoietic cells and PGCs. We identified 6 DNase I hypersensitive sites (HS1-HS6) within the promoter and first intron of the mouse Kit gene and developed mouse lines expressing transgenic green fluorescent protein (GFP) under the control of these regulatory elements. A construct driven by the Kit promoter and including all 6 HS sites is highly expressed during mouse development in Kit+ cells including PGCs and hematopoietic progenitors (erythroid blast-forming units and mixed colony-forming units). In contrast, the Kit promoter alone (comprising HS1) is sufficient to drive low-level GFP expression in PGCs, but unable to function in hematopoietic cells. Hematopoietic expression further requires the addition of the intronproximal HS2 fragment; HS2 also greatly potentiates the activity in PGCs. Thus, HS2 acts as an enhancer integrating transcriptional signals common to 2 developmentally unrelated stem cell/progenitor lineages. Optimal hematopoietic expression further requires HS3-HS6.
authors.affiliation: Dipartimento Biotecnologie e Bioscienze, Università Milano-Bicocca-Piazza delle Scienze, 2 Milan, Italy.
authors.forename: Linda A
authors.initials: LA
authors.lastname: Cairns
authors.forename: Emanuela
authors.initials: E
authors.lastname: Moroni
authors.forename: Elena
authors.initials: E
authors.lastname: Levantini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Giorgetti
authors.forename: Francesca G
authors.initials: FG
authors.lastname: Klinger
authors.forename: Simona
authors.initials: S
authors.lastname: Ronzoni
authors.forename: Laura
authors.initials: L
authors.lastname: Tatangelo
authors.forename: Cecilia
authors.initials: C
authors.lastname: Tiveron
authors.forename: Massimo
authors.initials: M
authors.lastname: De Felici
authors.forename: Susanna
authors.initials: S
authors.lastname: Dolci
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Magli
authors.forename: Barbara
authors.initials: B
authors.lastname: Giglioni
authors.forename: Sergio
authors.initials: S
authors.lastname: Ottolenghi
mesh_terms: D000818:Animals; D019070:Cell Lineage; D002478:Cells, Cultured; D003850:Deoxyribonuclease I; D004622:Embryo, Mammalian; D018507:Gene Expression Regulation, Developmental; D005809:Genes, Regulator; D005854:Germ Cells / Q000166:cytology*; D049452:Green Fluorescent Proteins; D006410:Hematopoiesis / Q000235:genetics; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D039902:Multipotent Stem Cells / Q000166:cytology; D011401:Promoter Regions, Genetic; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis / Q000235:genetics*; D014018:Tissue Distribution
chemical_list: D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D019009:Proto-Oncogene Proteins c-kit; D003850:Deoxyribonuclease I