Read-through Activation of Transcription in a Cellular Genomic Context

Read-through transcription from the adjacent E1a gene region is required for wild-type (wt) activity of the downstream adenovirus E1b promoter early after infection (read-through activation). However, whether a cellular chromosomal template can support read-through activation is not known. To address this issue, read-through activation was evaluated in the context of stably expressed templates in transfected cells. Inhibition of read-through transcription by insertion of a transcription termination sequence between the E1a and E1b promoters reduced downstream gene expression from stably integrated templates. The results indicate that the mechanism of read-through activation does not depend on the structure of early adenovirus nucleoprotein complexes, a structure that is likely to be different from that of cellular chromatin. Accordingly, this regulatory interaction could participate in the coordinated control of the expression of closely linked cellular genes

Germline variation at 8q24 and prostate cancer risk in men of European ancestry

Chromosome 8q24 is a susceptibility locus for multiple cancers, including prostate cancer. Here we combine genetic data across the 8q24 susceptibility region from 71,535 prostate cancer cases and 52,935 controls of European ancestry to define the overall contribution of germline variation at 8q24 to prostate cancer risk. We identify 12 independent risk signals for prostate cancer (p < 4.28 × 10−15), including three risk variants that have yet to be reported. From a polygenic risk score (PRS) model, derived to assess the cumulative effect of risk variants at 8q24, men in the top 1% of the PRS have a 4-fold (95%CI = 3.62–4.40) greater risk compared to the population average. These 12 variants account for ~25% of what can be currently explained of the familial risk of prostate cancer by known genetic risk factors. These findings highlight the overwhelming contribution of germline variation at 8q24 on prostate cancer risk which has implications for population risk stratification

Sequence-mediated regulation of adenovirus gene expression by repression of mRNA accumulation.

Gene expression in complex transcription units can be regulated at virtually every step in the production of mature cytoplasmic mRNA, including transcription initiation, elongation, termination, pre-mRNA processing, nucleus-to-cytoplasm mRNA transport, and alterations in mRNA stability. We have been characterizing alternative poly(A) site usage in the adenovirus major late transcription unit (MLTU) as a model for regulation at the level of pre-mRNA 3'-end processing. The MLTU contains five polyadenylation sites (L1 through L5). The promoter proximal site (L1) functions as the dominant poly(A) site during the early stage of adenovirus infection and in plasmid transfections when multiple poly(A) sites are present at the 3' end of a reporter plasmid. In contrast, stable mRNA processed at all five poly(A) sites is found during the late stage of adenovirus infection, after viral DNA replication has begun. Despite its dominance during early infection, L1 is a comparatively poor substrate for 3'-end RNA processing both in vivo and in vitro. In this study we have investigated the basis for the early L1 dominance. We have found that mRNA containing an unprocessed L1 poly(A) site is compromised in its ability to enter the steady-state pool of stable mRNA. This inhibition, which affects either the nuclear stability or nucleus-to-cytoplasm transport of the pre-mRNA, requires a cis-acting sequence located upstream of the L1 poly(A) site