Necdin acts as a transcriptional repressor that interacts with multiple guanosine clusters.
Necdin is a growth suppressor expressed predominantly in postmitotic neurons, and ectopic expression of this protein suppresses cell growth. Here we report that Necdin directly binds to specific DNA sequences and serves as a transcriptional repressor. Polyhistidine-tagged Necdin was used for selection of random-sequence oligonucleotides by polymerase chain reaction-based amplification. Necdin recognized guanosine (G)-rich sequences that encompass multiple G clusters and intervening mono- or di-nucleotides of A, T and C. These sequences, termed GN boxes, resemble multiply aligned forms of the canonical GC box which is recognized by Sp family members. Necdin directly bound to a GN box consisting of contiguous two GC boxes with four G clusters, but not to a single GC box with two G clusters, whereas Sp1 bound to both. In a reporter system using Drosophila Schneider Line 2 cells, Necdin repressed Sp1-dependent activity of mouse c-myc P1 promoter that contains a typical GN box. Deletion of the GN box from the c-myc P1 promoter or its conversion to the single GC box abolished the Necdin-dependent repression. These results suggest that Necdin modulates gene transcription via the GN box that is potentially recognized by GC box-targeting Sp family members.
Matsumoto
K
K
Division of Regulation of Macromolecular Functions, Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
Taniura
H
H
Uetsuki
T
T
Yoshikawa
K
K
D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D016259:Genes, myc / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D006151:Guanosine / Q000235:genetics / Q000378:metabolism*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D016329:Sp1 Transcription Factor; C069766:necdin; D006151:Guanosine; D004247:DNA; D008156:Luciferases