Coronaviruses (CoV), like other positive-stranded RNA viruses, redirect and rearrange host cell membranes for use as part of the viral genome replication and transcription machinery. Specifically, coronaviruses induce the formation of double-membrane vesicles in infected cells. Although these double-membrane vesicles have been well characterized, the mechanism behind their formation remains unclear, including which viral proteins are responsible. Here, we use transfection of plasmid constructs encoding full-length versions of the three transmembrane-containing nonstructural proteins (nsps) of the severe acute respiratory syndrome (SARS) coronavirus to examine the ability of each to induce double-membrane vesicles in tissue culture. nsp3 has membrane disordering and proliferation ability, both in its full-length form and in a C-terminal-truncated form. nsp3 and nsp4 working together have the ability to pair membranes. nsp6 has membrane proliferation ability as well, inducing perinuclear vesicles localized around the microtubule organizing center. Together, nsp3, nsp4, and nsp6 have the ability to induce double-membrane vesicles that are similar to those observed in SARS coronavirus-infected cells. This activity appears to require the full-length form of nsp3 for action, as double-membrane vesicles were not seen in cells coexpressing the C-terminal truncation nsp3 with nsp4 and nsp6.

Although global methylation patterns are similar, there are differences in methylation of specific genes in IVF compared to NIFT conceptions, leading to altered gene expression. PTCRA was differentially methylated and downregulated in IVF conceptions, warranting further investigation. It remains to be determined whether these changes affect placentation and whether it is due to the more profound underlying infertility requiring IVF, yet these data provide unique insight into the first-trimester placental epigenome.

Background Multiple testing to understand global changes in gene expression based on genetic and epigenetic modifications is evolving. Chorionic villi, obtained for prenatal testing, is limited, but can be used to understand ongoing human pregnancies. However, optimal storage, processing and utilization of CVS for multiple platform testing has not been established. Results Leftover CVS samples were flash-frozen or preserved in RNAlater. Modifications to standard isolation kits were performed to isolate quality DNA and RNA from samples as small as 2–5 mg. RNAlater samples had significantly higher RNA yields and quality and were successfully used in microarray and RNA-sequencing (RNA-seq). RNA-seq libraries generated using 200 vs. 800 ng RNA showed similar biological coefficients of variation. RNAlater samples had lower DNA yields and quality, which improved by heating the elution buffer to 70°C. Purification of DNA was not necessary for bisulfite-conversion and genome-wide methylation profiling. CVS cells were propagated and continue to express genes found in freshly-isolated chorionic villi. Conclusions CVS samples preserved in RNAlater are superior. Our optimized techniques provide specimens for genetic, epigenetic and gene expression studies from a single small sample which can be used to develop diagnostics and treatments using a systems biology approach in the prenatal period.

ObjectivePerianal Crohn’s disease (pCD) occurs in up to 40% of patients with CD and is associated with poor quality of life, limited treatment responses and poorly understood aetiology. We performed a genetic association study comparing CD subjects with and without perianal disease and subsequently performed functional follow-up studies for a pCD associated SNP inComplement Factor B(CFB).DesignImmunochip-based meta-analysis on 4056 pCD and 11 088 patients with CD from three independent cohorts was performed. Serological and clinical variables were analysed by regression analyses. Risk allele of rs4151651 was introduced into human CFB plasmid by site-directed mutagenesis. Binding of recombinant G252 or S252 CFB to C3b and its cleavage was determined in cell-free assays. Macrophage phagocytosis in presence of recombinant CFB or serum fromCFBrisk, or protective CD or healthy subjects was assessed by flow cytometry.ResultsPerianal complications were associated with colonic involvement, OmpC and ASCA serology, and serology quartile sum score. We identified a genetic association for pCD (rs4151651), a non-synonymous SNP (G252S) inCFB, in all three cohorts. Recombinant S252 CFB had reduced binding to C3b, its cleavage was impaired, and complement-driven phagocytosis and cytokine secretion were reduced compared with G252 CFB. Serine 252 generates a de novo glycosylation site in CFB. Serum from homozygous risk patients displayed significantly decreased macrophage phagocytosis compared with non-risk serum.ConclusionpCD-associated rs4151651 inCFBis a loss-of-function mutation that impairs its cleavage, activation of alternative complement pathway, and pathogen phagocytosis thus implicating the alternative complement pathway and CFB in pCD aetiology.