The papillomavirus E2 regulatory protein has essential roles in viral transcription and the initiation of viral DNA replication as well as for viral genome maintenance. Brd4 has recently been identified as a major E2-interacting protein and, in the case of the bovine papillomavirus type 1, serves to tether E2 and the viral genomes to mitotic chromosomes in dividing cells, thus ensuring viral genome maintenance. We have explored the possibility that Brd4 is involved in other E2 functions. By analyzing the binding of Brd4 to a series of alanine-scanning substitution mutants of the human papillomavirus type 16 E2 N-terminal transactivation domain, we found that amino acids required for Brd4 binding were also required for transcriptional activation but not for viral DNA replication. Functional studies of cells expressing either the C-terminal domain of Brd4 that can bind E2 and compete its binding to Brd4 or short interfering RNA to knock down Brd4 protein levels revealed a role for Brd4 in the transcriptional activation function of E2 but not for its viral DNA replication function. Therefore, these studies establish a broader role for Brd4 in the papillomavirus life cycle than as the chromosome tether for E2 during mitosis.The papillomaviruses (PVs) are small DNA viruses that are etiologic agents for papillomas and warts in a variety of higher vertebrates including humans. Specific human papillomaviruses (HPVs) have been associated with some human cancers, most notably cervical cancer (58). The papillomaviruses establish long-term, persistent infections of squamous epithelial cells, and the viral life cycle is tightly linked with the differentiation program of the host cell (21). In the infected dividing basal cells of the epithelium, the viral DNA is maintained as a stable plasmid. Vegetative viral DNA replication occurs only in the more differentiated squamous epithelial cells. Bovine papillomavirus (BPV) DNA remains extrachromosomal in transformed rodent cells, a system that has served as a useful model for studying viral genome maintenance (28).The papillomavirus E2 protein has important roles in regulating viral transcription, in enhancing E1-dependent viral DNA replication, and in genome maintenance (21). E2 is a DNA binding protein that was first identified as a transcriptional activator (46). Subsequent studies established that E2 can also repress some genes, depending upon the location of its cognate binding sites within the promoter region (49). Indeed, E2 functions to repress the promoter directing the E6 and E7 viral oncogenes in the cancer-associated HPV type 16 (HPV16) and HPV18 genomes (38). For viral genome replication, E2 binds the viral helicase E1 and guides it to the origin of replication in the process of initiating origin-dependent viral DNA replication (6, 34). For genome maintenance, E2 has been shown to associate with mitotic chromosomes and, in doing so, to anchor the viral genomes to the host chromosomes during mitosis (4,22,31,35,44). The structure of E2 resembles that of a prototypic tr...

Consequently, dynamic rearrangements in central carbon metabolism seem to be of major importance for eukaryotic redox sensing, and represent a novel class of dynamic gene expression regulators.

Prostate cancer is the second most common cancer among men worldwide. Alterations in the DNA methylation pattern can be one of the leading causes for prostate cancer formation. This study is the fi rst high-throughput sequencing study investigating genome-wide DNA methylation patterns in a large cohort of 51 tumor and 53 benign prostate samples using methylated DNA immunoprecipitation sequencing. Comparative analyses identifi ed more than 147,000 cancer-associated epigenetic alterations. In addition, global methylation patterns show signifi cant differences based on the TMPRSS2-ERG rearrangement status. We propose the hypermethylation of miR-26a as an alternative pathway of ERG rearrangement-independent EZH2 activation. The observed increase in differential methylation events in fusion-negative tumors can explain the tumorigenic process in the absence of genomic rearrangements. SIGNIFICANCE:In contrast to TMPRSS2-ERG -rearranged tumors, the pathomechanism for gene fusionnegative tumors is completely unclear. Using a sequencing-based approach, our work uncovers signifi cant global epigenetic alterations in TMPRSS2-ERG gene fusion-negative tumors and provides a mechanistic explanation for the tumor formation process. Cancer Discov; 2(11); 1024-35.