Host Cell Factor-1 Recruitment to E2F-Bound and Cell-Cycle-Control Genes Is Mediated by THAP11 and ZNF143

Abstract

Summary Host cell factor-1 (HCF-1) is a metazoan transcriptional co-regulator essential for cell cycle progression and cell proliferation. Current models suggest a mechanism whereby HCF-1 functions as a direct co-regulator of E2F proteins, facilitating the expression of genes necessary for cell proliferation. In this report, we show that HCF-1 recruitment to numerous E2F-bound promoters is mediated by the concerted action of zinc finger transcription factors THAP11 and ZNF143, rather than E2F proteins directly. THAP11, ZNF143, and HCF-1 form a mutually dependent complex on chromatin, which is independent of E2F occupancy. Disruption of the THAP11/ZNF143/HCF-1 complex results in altered expression of cell cycle control genes and leads to reduced cell proliferation, cell cycle progression, and cell viability. These data establish a new model which suggests that a THAP11/ZNF143/HCF-1 complex is a critical component of the transcriptional regulatory network governing cell proliferation.

Genomic Determinants of THAP11/ZNF143/HCFC1 Complex Recruitment to Chromatin

“…This observation is consistent with in vitro electrophoretic mobility shift assays (EMSAs) indicating that mutations in the TCCCA motif interfere with ZNF143 DNA binding activity. Additionally, we observed significant depletion of THAP11 and HCFC1 chromatin occupancy, consistent with our previous observation of THAP11/HCFC1 subcomplex dependency on ZNF143 (21). An AGC mutation in the ACTACA submotif (mutA1) had a similar effect on THAP11 and HCFC1 occupancy; however, ZNF143 binding was affected less severely at the ESCO2 and AP2S1 promoters than with the TTC mutation (mutB1) (Fig.…”

“…Thus far, data from in vitro experiments have suggested that THAP11 and ZNF143 compete for binding to these DNA sequences (28). In contrast to these results, observations in our laboratory suggest that, in vivo, THAP11, ZNF143, and HCFC1 are mutually dependent on chromatin associations at gene promoters containing the SBS2 motif and cooccupy the same genomic loci (21). Thus, the mechanism of THAP11 binding to chromatin and the exact target sequence that its THAP domain recognizes remain uncertain.…”

“…As representatives of gene promoters harboring the SBS2 motif, we selected the AP2S1, ESCO2, and OPHN1 genes. These promoters contain a single SBS2 motif; are bound by THAP11, ZNF143, and HCFC1 at readily detectable levels; and were previously studied in our laboratory (21,33) and other laboratories (29).…”

“…In order to address the apparent inconsistency between in vitro and in vivo observations (21,28,36) and to elucidate the role of the ACTACA submotif found adjacent to the ZNF143 core motif, we established an in vivo system that allowed us to analyze the binding of the THAP11/ZNF143/ HCFC1 complex on a chromosomally integrated DNA template, the sequence of which we could efficiently manipulate. We constructed retroviral plasmids that incorporate 260 to 550 nucleotides of native ZNF143 target gene promoters, including the transcriptional start site and ϳ70 to 300 nucleotides of the 5= UTR.…”

“…Initially, the role of HCFC1 in cell proliferation and cell cycle progression had been attributed to its association with members of the E2F family of transcription factors, E2F1 and E2F4, and recruitment to promoters of cell cycle control genes (19,20). Nonetheless, a recent study in our laboratory revealed that HCFC1 recruitment to the promoters of these genes is largely mediated by the coordinated action of the THAP domain-containing protein 11 (THAP11) and zinc finger protein 143 (ZNF143) transcription factors and is independent of chromatin occupancy by E2F proteins (21).…”