Molecular and Genetic Evidence for a Virus-Encoded Glycosyltransferase Involved in Protein Glycosylation

AbstractThe major capsid protein, Vp54, of chlorella virus PBCV-1 is a glycoprotein that contains either one glycan of ∼30 sugar residues or two similar glycans of ∼15 residues. Previous analysis of PBCV-1 antigenic mutants that contained altered Vp54 glycans led to the conclusion that unlike other glycoprotein-containing viruses, most, if not all, of the enzymes involved in the synthesis of the Vp54 glycan are probably encoded by PBCV-1 (I.-N. Wang et al., 1993, Proc. Natl. Acad. Sci. USA 90, 3840–3844). In this report we used molecular and genetic approaches to begin to identify these virus genes. Comparing the deduced amino acid sequences of the putative 375 PBCV-1 protein-encoding genes to databases identified seven potential glycosyltransferases. One gene, designated a64r, encodes a 638-amino-acid protein that has four motifs conserved in “Fringe type” glycosyltransferases. Analysis of 13 PBCV-1 antigenic mutants revealed mutations in a64r that correlated with a specific antigenic variation. Dual-infection experiments with different antigenic mutants indicated that viruses that contained wild-type a64r could complement and recombine with viruses that contained mutant a64r to form wild-type virus. Therefore, we conclude that a64r encodes a glycosyltransferase involved in synthesizing the Vp54 glycan. This is the first report of a virus-encoded glycosyltransferase involved in protein glycosylation

Clinical characteristics and outcomes of colorectal cancer in the ColoCare Study: Differences by age of onset

Early-onset colorectal cancer has been on the rise in Western populations. Here, we compare patient characteristics between those with early- (\u3c50 years) vs. late-onset (≥50 years) disease in a large multinational cohort of colorectal cancer patients

NF-Y Behaves as a Bifunctional Transcription Factor That Can Stimulate or Repress the FGF-4 Promoter in an Enhancer-Dependent Manner

NF-Y is a bifunctional transcription factor capable of activating or repressing transcription. NF-Y specifically recognizes CCAAT box motifs present in many eukaryotic promoters. The mechanisms involved in regulating its activity are poorly understood. Previous studies have shown that the FGF-4 promoter is regulated positively by its CCAAT box and NF-Y in embryonal carcinoma (EC) cells where the distal enhancer of the FGF-4 gene is active. Here, we demonstrate that the CCAAT box functions as a negative cis-regulatory element when cis-regulatory elements of the FGF-4 enhancer are disrupted, or after EC cells differentiate and the FGF-4 enhancer is inactivated. We also demonstrate that NF-Y mediates the repression of the CCAAT box and that NF-Y associates with the endogenous FGF-4 gene in both EC cells and EC-differentiated cells. Importantly, we also determined that the orientation and the position of the CCAAT box are critical for its role in regulating the FGF-4 promoter. Together, these studies demonstrate that the distal enhancer of the FGF-4 gene determines whether the CCAAT box of the FGF-4 promoter functions as a positive or a negative cis-regulatory element. In addition, these studies are consistent with NF-Y playing an architectural role in its regulation of the FGF-4 promoter

Transcriptional Regulation of the Murine \u3ci\u3eElf3\u3c/i\u3e Gene in Embryonal Carcinoma Cells and Their Differentiated Counterparts: Requirement for a Novel Upstream Regulatory Region

The transcription factor Elf3, which is one of over 25 Ets family members, is expressed in a wide variety of carcinomas and has been shown to promote the transcription of many genes implicated in cancer. To understand how the Elf3 gene is regulated at the transcriptional level, we probed its 5’-flanking region, and we report here the identification of both proximal and distal regions that regulate murine Elf3 promoter activity. In addition to mapping the transcription start site of the Elf3 gene, the work described in this study identifies four cisregulatory elements in the proximal promoter region of the gene. These include a cis-regulatory element previously designated ESE, a κB site, a POU motif, and a CCAAT box. In addition, we demonstrate that a novel 94 bp region 2 kb upstream of the transcription start site significantly elevates Elf3 promoter activity in F9-differentiated cells, but not in the parental F9 embryonal carcinoma (EC) cells. This region appears to be largely responsible for the increase in Elf3 promoter activity that accompanies the differentiation of embryonal carcinoma cells

Clinical Characteristics and Outcomes of Colorectal Cancer in the ColoCare Study: Differences by Age of Onset.

Early-onset colorectal cancer has been on the rise in Western populations. Here, we compare patient characteristics between those with early- (<50 years) vs. late-onset (≥50 years) disease in a large multinational cohort of colorectal cancer patients (n = 2193). We calculated descriptive statistics and assessed associations of clinicodemographic factors with age of onset using mutually-adjusted logistic regression models. Patients were on average 60 years old, with BMI of 29 kg/m2, 52% colon cancers, 21% early-onset, and presented with stage II or III (60%) disease. Early-onset patients presented with more advanced disease (stages III-IV: 63% vs. 51%, respectively), and received more neo and adjuvant treatment compared to late-onset patients, after controlling for stage (odds ratio (OR) (95% confidence interval (CI)) = 2.30 (1.82-3.83) and 2.00 (1.43-2.81), respectively). Early-onset rectal cancer patients across all stages more commonly received neoadjuvant treatment, even when not indicated as the standard of care, e.g., during stage I disease. The odds of early-onset disease were higher among never smokers and lower among overweight patients (1.55 (1.21-1.98) and 0.56 (0.41-0.76), respectively). Patients with early-onset colorectal cancer were more likely to be diagnosed with advanced stage disease, to have received systemic treatments regardless of stage at diagnosis, and were less likely to be ever smokers or overweight