title: A multimerizing transcription factor of sea urchin embryos capable of looping DNA.
abstract: SpGCF1 is a recently cloned sea urchin transcription factor that recognizes target sites in several different sea urchin genes. We find that in gel-shift experiments this factor is able to multimerize. A quantitative simulation of the gel-shift results suggests that SpGCF1 molecules that are bound to DNA target sites may also bind to one another, thus associating several DNA probe molecules. SpGCF1 might therefore be able to loop DNA molecules bearing its target sites at distant locations. We demonstrate this prediction by electron microscopy, and using the well-characterized cis-regulatory domain of the CyIIIa cytoskeletal actin gene, we show that the loop conformations predicted from the known SpGCF1 target site locations are actually formed in vitro. We speculate that the multimerization of this factor in vivo may function to bring distant regions of extended regulatory domains into immediate proximity so that they can interact with one another.
authors.affiliation: Division of Biology 156-29, California Institute of Technology, Pasadena 91125, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Zeller
authors.forename: J D
authors.initials: JD
authors.lastname: Griffith
authors.forename: J G
authors.initials: JG
authors.lastname: Moore
authors.forename: C V
authors.initials: CV
authors.lastname: Kirchhamer
authors.forename: R J
authors.initials: RJ
authors.lastname: Britten
authors.forename: E H
authors.initials: EH
authors.lastname: Davidson
mesh_terms: D000199:Actins / Q000096:biosynthesis; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D012045:Regulatory Sequences, Nucleic Acid; D012617:Sea Urchins / Q000196:embryology*; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D000199:Actins; D015342:DNA Probes; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; C092981:SpGCF1 protein, Strongylocentrotus purpuratus; D014157:Transcription Factors; D004247:DNA