DNA recognition by splicing variants of the Wilms' tumor suppressor, WT1.
The Wilms' tumor suppressor, WT1, is a zinc finger transcriptional regulator which exists as multiple forms owing to alternative mRNA splicing. The most abundant splicing variants contain a nine-nucleotide insertion encoding lysine, threonine, and serine (KTS) in the H-C link region between the third and fourth WT1 zinc fingers which disrupts binding to a previously defined WT1-EGR1 binding site. We have identified WT1[+KTS] binding sites in the insulin-like growth factor II gene and show that WT1[+KTS] represses transcription from the insulin-like growth factor II P3 promoter. The highest affinity WT1[+KTS] DNA binding sites included nucleotide contacts involving all four WT1 zinc fingers. We also found that different subsets of three WT1 zinc fingers could bind to distinct DNA recognition elements. A tumor-associated, WT1 finger 3 deletion mutant was shown to bind to juxtaposed nucleotide triplets for the remaining zinc fingers 1, 2, and 4. The characterization of novel WT1 DNA recognition elements adds a new level of complexity to the potential gene regulatory activity of WT1. The results also present the possibility that altered DNA recognition by the dominant WT1 zinc finger 3 deletion mutant may contribute to tumorigenesis.
Drummond
I A
IA
Harvard Medical School, Department of Medicine, Beth Israel Hospital, Boston, Massachusetts 02215.
Rupprecht
H D
HD
Rohwer-Nutter
P
P
Lopez-Guisa
J M
JM
Madden
S L
SL
Rauscher
F J
FJ
Sukhatme
V P
VP
D017398:Alternative Splicing; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D016162:Genes, Wilms Tumor; D014644:Genetic Variation; D005822:Genetic Vectors; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis; D007700:Kinetics; D008745:Methylation; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D025721:WT1 Proteins; D016335:Zinc Fingers / Q000235:genetics
D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D025721:WT1 Proteins; D007335:Insulin-Like Growth Factor II; D004247:DNA