LIN54 is an essential core subunit of the DREAM/LINC complex that binds to the cdc2 promoter in a sequence-specific manner.
Recently, the conserved human LINC/DREAM complex has been described as an important regulator of cell cycle genes. LINC consists of a core module that dynamically associates with E2F transcription factors, p130 and the B-MYB transcription factor in a cell cycle-dependent manner. In this study, we analyzed the evolutionary conserved LIN54 subunit of LINC. We found that LIN54 is required for cell cycle progression. Protein interaction studies demonstrated that a predicted helix-coil-helix motif is required for the interaction of LIN54 with p130 and B-MYB. In addition, we found that the cysteine-rich CXC domain of LIN54 is a novel DNA-binding domain that binds to the cdc2 promoter in a sequence-specific manner. We identified two binding sites for LIN54 in the cdc2 promoter, one of which overlaps with the cell cycle homology region at the transcriptional start site. Gel shift assays suggested that, in quiescent cells, the binding of LIN54 at the cell cycle homology region is stabilized by the binding of E2F4 to the adjacent cell cycle-dependent element. Our data demonstrate that LIN54 is an important and integral subunit of LINC.
Schmit
Fabienne
F
Department of Physiological Chemistry I, Biocenter, University of Wuerzburg, Germany.
Cremer
Sarah
S
Gaubatz
Stefan
S
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D016203:CDC2 Protein Kinase; D002453:Cell Cycle / Q000235:genetics; D002460:Cell Line; D019926:Cyclin B / Q000235:genetics*; D018844:Cyclin-Dependent Kinases; D004247:DNA / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051605:Kv Channel-Interacting Proteins / Q000737:chemistry* / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism*; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D016203:CDC2 Protein Kinase; D019926:Cyclin B; D018844:Cyclin-Dependent Kinases; D004247:DNA; D051605:Kv Channel-Interacting Proteins; D046912:Multiprotein Complexes; D021122:Protein Subunits; D011994:Recombinant Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; C496749:KCNIP3 protein, human; C523006:LIN54 protein, human; C528899:CDK1 protein, human