Rescue of the lethal scl(-/-) phenotype by the human SCL locus.
The stem cell leukemia (SCL) gene encodes a basic helix-loop-helix transcription factor with a critical role in the development of both blood and endothelium. Loss-of-function studies have shown that SCL is essential for the formation of hematopoietic stem cells, for subsequent erythroid development and for yolk sac angiogenesis. SCL exhibits a highly conserved pattern of expression from mammals to teleost fish. Several murine SCL enhancers have been identified, each of which directs reporter gene expression in vivo to a subdomain of the normal SCL expression pattern. However, regulatory elements necessary for SCL expression in erythroid cells remain to be identified and the size of the chromosomal domain needed to support appropriate SCL transcription is unknown. Here we demonstrate that a 130-kilobase (kb) yeast artificial chromosome (YAC) containing the human SCL locus completely rescued the embryonic lethal phenotype of scl(-/-) mice. Rescued YAC(+) scl(-/-) mice were born in appropriate Mendelian ratios, were healthy and fertile, and exhibited no detectable abnormality of yolk sac, fetal liver, or adult hematopoiesis. The human SCL protein can therefore substitute for its murine homologue. In addition, our results demonstrate that the human SCL YAC contains the chromosomal domain necessary to direct expression to the erythroid lineage and to all other tissues in which SCL performs a nonredundant essential function.
Sinclair
Angus M
AM
University of Cambridge, Department of Haematology, Cambridge Institute for Medical Research, Hills Road, Cambridge, CB2 2XY, United Kingdom.
Bench
Anthony J
AJ
Bloor
Adrian J C
AJ
Li
Juan
J
Göttgens
Berthold
B
Stanley
Maureen L
ML
Miller
Jane
J
Piltz
Sandie
S
Hunter
Susie
S
Nacheva
Elisabeth P
EP
Sanchez
María-José
MJ
Green
Anthony R
AR
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D018244:Chromosomes, Artificial, Yeast; D003114:Colony-Forming Units Assay; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics*; D005434:Flow Cytometry; D017353:Gene Deletion; D005786:Gene Expression Regulation; D005804:Genes, Lethal; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D006801:Humans; D007938:Leukemia / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics*; D015183:Restriction Mapping; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics*
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C489366:Tal1 protein, mouse; C067143:TAL1 protein, human