A nuclear protein factor binds specifically to the 3'-regulatory module of the long-interspersed-nuclear-element-like Dictyostelium repetitive element.
The Dictyostelium repetitive element DRE integrates in a position-specific manner upstream of tRNA genes in the Dictyostelium discoideum genome. DRE has structural similarities to the group of long interspersed nuclear elements, whose replication mechanism is poorly understood. The C-module at the 3' end of DRE encodes a regulatory cis-acting sequence that contains an RNA polymerase II promoter. This promoter directs the synthesis of RNAs that are thought to play a critical role in DRE transposition. In this study, we describe the identification of a nuclear protein factor that binds to the C-module in a sequence-specific manner. The C-module-binding factor (CMBF) recognizes three DNA sequence motifs that contain homopolymeric (dT) stretches of variable lengths, but does not bind to a standard RNA polymerase II promoter from D, discoideum. Analysis of highly CMBF-enriched fractions and glycerol gradient sedimentation of CMBF suggest that the factor exists as a monomeric 115-kDa protein. Possible roles of CMBF in DRE transposition are discussed.
Institut für Pharmazeutische Biologie, Universität Frankfurt/Main (Biozentrum), Frankfurt, Germany.
A
A
Geier
J
J
Horn
T
T
Dingermann
T
T
Winckler
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002499:Centrifugation, Density Gradient; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004023:Dictyostelium / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D015966:Gene Expression Regulation, Fungal; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins