title: DNA-binding dependent and independent functions of WT1 protein during human hematopoiesis.
abstract: The Wilms tumor gene 1 (WT1) encodes a zinc-finger-containing transcription factor highly expressed in immature hematopoietic progenitor cells. Overexpression and presence of somatic mutations in acute leukemia indicate a role for WT1 in the pathogenesis of leukemia. CD34+ progenitor cells were transduced with one splice variant of human WT1 without the KTS insert in the zinc-finger domain, WT1(+/-), and with a deleted mutant of WT1 lacking the entire zinc-finger region, WT1(delZ), thus incapable of binding DNA. We show that inhibition of erythroid colony formation and differentiation is absolutely dependent on the DNA-binding zinc-finger domain of WT1. Unexpectedly, however, WT1(delZ) was equally effective as wild type protein in the reduction of myeloid clonogenic growth as well as in stimulation of myeloid differentiation, as judged by the expression of cell surface CD11b. Expression of neither WT1(+/-) nor WT1(delZ) upregulated mRNA for the cdk inhibitor p21(Waf1/Cip1) or p27Kip1. Our results demonstrate that WT1 affects proliferation and differentiation in erythroid and myeloid cells by different molecular mechanisms, and suggest that mutations affecting the zinc-finger domain of WT1 could interfere with normal differentiation in the pathogenesis of leukemia.
authors.affiliation: Department of Hematology, Lund University, BMC, C14, S-221 84 Lund, Sweden.
authors.forename: Emelie
authors.initials: E
authors.lastname: Svensson
authors.forename: Helena
authors.initials: H
authors.lastname: Eriksson
authors.forename: Christos
authors.initials: C
authors.lastname: Gekas
authors.forename: Tor
authors.initials: T
authors.lastname: Olofsson
authors.forename: Johan
authors.initials: J
authors.lastname: Richter
authors.forename: Urban
authors.initials: U
authors.lastname: Gullberg
mesh_terms: D018952:Antigens, CD34 / Q000096:biosynthesis / Q000097:blood / Q000502:physiology; D018797:Cell Cycle Proteins / Q000187:drug effects / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D015672:Erythroid Precursor Cells / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D005822:Genetic Vectors / Q000235:genetics / Q000502:physiology; D006410:Hematopoiesis / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D012190:Retroviridae / Q000235:genetics / Q000502:physiology; D017384:Sequence Deletion; D014161:Transduction, Genetic; D025521:Tumor Suppressor Proteins / Q000187:drug effects / Q000235:genetics; D025721:WT1 Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D018952:Antigens, CD34; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D025521:Tumor Suppressor Proteins; D025721:WT1 Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004247:DNA