Regulation of the stem cell leukemia (SCL) gene: a tale of two fishes.
The stem cell leukemia (SCL) gene encodes a tissue-specific basic helix-loop-helix (bHLH) protein with a pivotal role in hemopoiesis and vasculogenesis. Several enhancers have been identified within the murine SCL locus that direct reporter gene expression to subdomains of the normal SCL expression pattern, and long-range sequence comparisons of the human and murine SCL loci have identified additional candidate enhancers. To facilitate the characterization of regulatory elements, we have sequenced and analyzed 33 kb of the SCL genomic locus from the pufferfish Fugu rubripes, a species with a highly compact genome. Although the pattern of SCL expression is highly conserved from mammals to teleost fish, the genes flanking pufferfish SCL were unrelated to those known to flank both avian and mammalian SCL genes. These data suggest that SCL regulatory elements are confined to the region between the upstream and downstream flanking genes, a region of 65 kb in human and 8.5 kb in pufferfish. Consistent with this hypothesis, the entire 33-kb pufferfish SCL locus directed appropriate expression to hemopoietic and neural tissue in transgenic zebrafish embryos, as did a 10.4-kb fragment containing the SCL gene and extending to the 5' and 3' flanking genes. These results demonstrate the power of combining the compact genome of the pufferfish with the advantages that zebrafish provide for studies of gene regulation during development. Furthermore, the pufferfish SCL locus provides a powerful tool for the manipulation of hemopoiesis and vasculogenesis in vivo.
Barton
L M
LM
Department of Hematology, Cambridge Institute for Medical Research, University of Cambridge, Addenbrookes Hospital, Cambridge CB2 2XY, United Kingdom.
Gottgens
B
B
Gering
M
M
Gilbert
J G
JG
Grafham
D
D
Rogers
J
J
Bentley
D
D
Patient
R
R
Green
A R
AR
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D051792:Basic Helix-Loop-Helix Proteins; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D005399:Fishes / Q000235:genetics*; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D015321:Gene Rearrangement; D005809:Genes, Regulator; D018257:Helix-Loop-Helix Motifs; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins
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; D029961:Zebrafish Proteins; C489367:tal1 protein, zebrafish