Expression pattern of zebrafish tcf7 suggests unexplored domains of Wnt/beta-catenin activity.
Tcf/Lef transcription factors play an important role in mediating canonical Wnt signaling. When bound by beta-catenin, Tcf/Lef proteins either activate or de-repress gene transcription. In zebrafish, four members have been identified: Lef1, Tcf3, Tcf3b, and Tcf4. Here, we report the cloning and expression of the tcf7 gene. Forms of Tcf7 expressed in the embryo contain two highly conserved regions: an N-terminal beta-catenin binding domain and a C-terminal HMG domain. Tcf7 lacks a putative Groucho corepressor binding site, suggesting that, like Lef1, it functions as a transcriptional activator. We isolated three C-terminal splice variants of tcf7 corresponding to human B, C, and D isoforms. tcf7 expression overlaps with lef1 expression maternally, in the tail bud, fin buds, and paraxial mesoderm, and we expect that the two genes function redundantly in those areas. tcf7 is also expressed in nonoverlapping areas such as the prechordal mesoderm, dorsal retina, and median fin fold, suggesting unique functions.
Veien
Eric S
ES
Program in Neuroscience, University of Utah, Salt Lake City, UT 84132, USA.
Grierson
Matthew J
MJ
Saund
Ranajeet S
RS
Dorsky
Richard I
RI
D000595:Amino Acid Sequence; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D001665:Binding Sites; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D051821:Lymphoid Enhancer-Binding Factor 1; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D012097:Repressor Proteins / Q000378:metabolism; D016415:Sequence Alignment; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D051153:Wnt Proteins; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*; D051176:beta Catenin
D051792:Basic Helix-Loop-Helix Proteins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; C497573:LEF1 protein, human; C497574:Lef1 protein, mouse; C503185:Tcf7 protein, zebrafish; C495269:ctnnb1 protein, zebrafish; C091023:gro protein, Drosophila