Molecular heterogeneity of regulatory elements of the mouse GATA-1 gene.
The GATA-1 gene encodes a transcription factor expressed in early multipotent haemopoietic progenitors, in more mature cells of the erythroid, megakaryocytic and other lineages, but not in late myeloid precursors; its function is essential for the normal development of the erythroid and megakaryocytic system. To define regulatory elements of the mouse GATA-1 gene, we mapped DNaseI-hypersensitive sites in nuclei of erythroid and haemopoietic progenitor cells. Five sites were detected. The two upstream sites, site 1 and site 2, represent a new and a previously defined erythroid enhancer respectively. The site 1 enhancer activity depends both on a GATA-binding site (also footprinted in vivo) and on several sites capable of binding relatively ubiquitous factors. A DNA fragment encompassing site 1, placed upstream of a GATA-1 minimal promoter, is able to drive expression of a simian virus 40 (SV40) T-antigen in the yolk sac, but not bone-marrow cells, obtained from mice transgenic for this construct, allowing in vitro establishment of immortalized yolk-sac cells. A similar construct including site 2, instead of site 1, and previously shown to be able to immortalize adult marrow cells is not significantly active in yolk-sac cells. Sites 4 and 5, located in the first large intron, have no enhancer activity; they include a long array of potential Ets-binding sites. MnlI restriction sites, overlapping some of the Ets sites, are highly accessible, in intact nuclei, to MnlI. Although these sites are present in all GATA-1-expressing cells studied, they are the only strong sites detectable in FDCP-mix multipotent progenitor cells, most of which do not yet express GATA-1. The data indicate that appropriate GATA-1 regulation may require the co-operation of different regulatory elements acting at different stages of development and cell differentiation.
Ronchi
A
A
Dipartimento di Genetica e di Biologia dei Microrganismi, Università di Milano, Italy.
Cirò
M
M
Cairns
L
L
Basilico
L
L
Corbella
P
P
Ricciardi-Castagnoli
P
P
Cross
M
M
Ghysdael
J
J
Ottolenghi
S
S
D000818:Animals; D001483:Base Sequence; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002460:Cell Line; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000235:genetics*; D003850:Deoxyribonuclease I / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D015672:Erythroid Precursor Cells / Q000502:physiology; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D018507:Gene Expression Regulation, Developmental; D006412:Hematopoietic Stem Cells / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection; D015017:Yolk Sac / Q000166:cytology
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494689:Gata1 protein, mouse; D014157:Transcription Factors; D003850:Deoxyribonuclease I