Kit regulatory elements required for expression in developing hematopoietic and germ cell lineages.
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.
Cairns
Linda A
LA
Dipartimento Biotecnologie e Bioscienze, Università Milano-Bicocca-Piazza delle Scienze, 2 Milan, Italy.
Moroni
Emanuela
E
Levantini
Elena
E
Giorgetti
Alessandra
A
Klinger
Francesca G
FG
Ronzoni
Simona
S
Tatangelo
Laura
L
Tiveron
Cecilia
C
De Felici
Massimo
M
Dolci
Susanna
S
Magli
Maria Cristina
MC
Giglioni
Barbara
B
Ottolenghi
Sergio
S
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
D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D019009:Proto-Oncogene Proteins c-kit; D003850:Deoxyribonuclease I