Identification of a Genetic Variation in ERAP1 Aminopeptidase that Prevents Human Cytomegalovirus miR-UL112-5p-Mediated Immunoevasion.

Herein, we demonstrate that HCMV miR-UL112-5p targets ERAP1, thereby inhibiting the processing and presentation of the HCMV pp65495-503 peptide to specific CTLs. In addition, we show that the rs17481334 G variant, naturally occurring in the ERAP1 3' UTR, preserves ERAP1 from miR-UL112-5p-mediated degradation. Specifically, HCMV miR-UL112-5p binds the 3' UTR of ERAP1 A variant, but not the 3' UTR of ERAP1 G variant, and, accordingly, ERAP1 expression is reduced both at RNA and protein levels only in human fibroblasts homozygous for the A variant. Consistently, HCMV-infected GG fibroblasts were more efficient in trimming viral antigens and being lysed by HCMV-peptide-specific CTLs. Notably, a significantly decreased HCMV seropositivity was detected among GG individuals suffering from multiple sclerosis, a disease model in which HCMV is negatively associated with adult-onset disorder. Overall, our results identify a resistance mechanism to HCMV miR-UL112-5p-based immune evasion strategy with potential implications for individual susceptibility to infection and other diseases.

Requirement for the E1 Helicase C-Terminal Domain in Papillomavirus DNA Replication In Vivo.

UNLABELLED: The papillomavirus (PV) E1 helicase contains a conserved C-terminal domain (CTD), located next to its ATP-binding site, whose function in vivo is still poorly understood. The CTD is comprised of an alpha helix followed by an acidic region (AR) and a C-terminal extension termed the C-tail. Recent biochemical studies on bovine papillomavirus 1 (BPV1) E1 showed that the AR and C-tail regulate the oligomerization of the protein into a double hexamer at the origin. In this study, we assessed the importance of the CTD of human papillomavirus 11 (HPV11) E1 in vivo, using a cell-based DNA replication assay. Our results indicate that combined deletion of the AR and C-tail drastically reduces DNA replication, by 85%, and that further truncation into the alpha-helical region compromises the structural integrity of the E1 helicase domain and its interaction with E2. Surprisingly, removal of the C-tail alone or mutation of highly conserved residues within the domain still allows significant levels of DNA replication (55%). This is in contrast to the absolute requirement for the C-tail reported for BPV1 E1 in vitro and confirmed here in vivo. Characterization of chimeric proteins in which the AR and C-tail from HPV11 E1 were replaced by those of BPV1 indicated that while the function of the AR is transferable, that of the C-tail is not. Collectively, these findings define the contribution of the three CTD subdomains to the DNA replication activity of E1 in vivo and suggest that the function of the C-tail has evolved in a PV type-specific manner. IMPORTANCE: While much is known about hexameric DNA helicases from superfamily 3, the papillomavirus E1 helicase contains a unique C-terminal domain (CTD) adjacent to its ATP-binding site. We show here that this CTD is important for the DNA replication activity of HPV11 E1 in vivo and that it can be divided into three functional subdomains that roughly correspond to the three conserved regions of the CTD: an alpha helix, needed for the structural integrity of the helicase domain, followed by an acidic region (AR) and a C-terminal tail (C-tail) that have been shown to regulate the oligomerization of BPV1 E1 in vitro. Characterization of E1 chimeras revealed that, while the function of the AR could be transferred from BPV1 E1 to HPV11 E1, that of the C-tail could not. These results suggest that the E1 CTD performs multiple functions in DNA replication, some of them in a virus type-specific manner.

Severe gastrointestinal dysmotility developed after treatment with gonadotropin-releasing hormone analogs.

BACKGROUND: Sporadic cases of abdominal pain and dysmotility has been described after treatment with gonadotropin-releasing hormone (GnRH) analogs. The aim of the present study was to scrutinize for patients with severe gastrointestinal complaints after treatment with GnRH analogs, to describe the expression of antibodies against progonadoliberin-2, GnRH1, GnRH receptor (GnRHR), luteinizing hormone (LH), and LH receptor in serum in these patients, and to search for possible triggers and genetic factors behind the development of this dysmotility. METHODS: Patients suffering from prolonged gastrointestinal complaints after treatment with GnRH analogs at the Department of Gastroenterology, Skåne University Hospital, were included. GnRHR and LH receptor (LHCGR) genes were exome-sequenced. Serum was analyzed by enzyme-linked immune sorbent assays for the presence of antibodies. Healthy blood donors and women treated with GnRH analogs because of in vitro fertilization (IVF) were used as controls. RESULTS: Seven patients with severe gastrointestinal complaints after GnRH treatment were identified, of whom six suffered from endometriosis. Several variants were found within the 11 exons of LHCGR. The minor allele G, at the single nucleotide polymorphism rs6755901, was detected in homozygosity in two patients (28.5%) who had developed chronic intestinal pseudo-obstruction and in 5.5% of the IVF controls. Three patients expressed IgM antibodies against progonadoliberin-2 and three against GnRH1 (42.9%) when cut off was set to a titer >97.5th percentile in blood donors. CONCLUSION: A high prevalence of endometriosis, polymorphism in the LHCGR and GnRH1 and progonadoliberin-2 antibodies in serum was found among the patients with severe dysmotility after treatment with GnRH analogs.

Expression and distribution of GnRH, LH, and FSH and their receptors in gastrointestinal tract of man and rat.

BACKGROUND: Gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) regulate the reproductive axis. Their analogs have been found to influence gastrointestinal activity and enteric neuronal survival. The aims of the study were to investigate expression and cellular distribution of GnRH, LH, and FSH and their receptors in human and rat gastrointestinal tract. METHODS: Bioinformatic analysis of publicly available microarray gene expression data and Real-Time PCR mRNA quantification were used to study mRNA expression levels of hormones and receptors in human intestinal tissue. Full-thickness sections of human ileum and colon, and rat stomach, ileum, and colon, were used for immunocytochemistry. Antibodies against human neuronal protein HuC/D (HuC/D) were used as general neuronal marker. LH and FSH, and GnRH-, LH-, and FSH receptor immunoreactive (IR) neurons were evaluated. RESULTS: GnRH1 mRNA was detected in both small and large intestine, whereas GnRH2 was mainly expressed in small intestine. Approximately 20% of both submucous and myenteric neurons displayed LH receptor immunoreactivity in human ileum and colon. In rat, 4%-9% of all enteric neurons in fundus and ileum, and 13% of submucous neurons and 21% of myenteric neurons in colon were LH receptor-IR. Neither mRNA (man) nor the fully expressed proteins (man and rat) of LH and FSH, or GnRH and FSH receptors, could be detected. CONCLUSIONS: GnRH1 and GnRH2 mRNA are expressed in human intestine. LH receptor-IR enteric neurons are found along the entire gastrointestinal tract in both man and rat.

Eight nucleotide substitutions inhibit splicing to HPV-16 3'-splice site SA3358 and reduce the efficiency by which HPV-16 increases the life span of primary human keratinocytes.

The most commonly used 3'-splice site on the human papillomavirus type 16 (HPV-16) genome named SA3358 is used to produce HPV-16 early mRNAs encoding E4, E5, E6 and E7, and late mRNAs encoding L1 and L2. We have previously shown that SA3358 is suboptimal and is totally dependent on a downstream splicing enhancer containingmultiple potential ASF/SF2 binding sites. Here weshow that only one of the predicted ASF/SF2 sites accounts for the majority of the enhancer activity. We demonstrate that single nucleotide substitutions in this predicted ASF/SF2 site impair enhancer function and that this correlates with less efficient binding to ASF/SF2 in vitro. We provide evidence that HPV-16 mRNAs that arespliced to SA3358 interact with ASF/SF2 in living cells. In addition,mutational inactivation of the ASF/SF2 site weakened the enhancer at SA3358 in episomal forms of the HPV-16 genome, indicating that the enhancer is active in the context of the full HPV-16 genome.This resulted in induction of HPV-16 late gene expression as a result of competition from late splice site SA5639. Furthermore, inactivation of the ASF/SF2 site of the SA3358 splicing enhancer reduced the ability of E6- and E7-encoding HPV-16 plasmids to increase the life span of primary keratinocytes in vitro, demonstrating arequirement for an intact splicing enhancer of SA3358 forefficient production of the E6 and E7 mRNAs. These results link the strength of the HPV-16 SA3358 splicing enhancer to expression of E6 and E7 and to the pathogenic properties of HPV-16.

The E1 proteins.

E1, an ATP-dependent DNA helicase, is the only enzyme encoded by papillomaviruses (PVs). It is essential for replication and amplification of the viral episome in the nucleus of infected cells. To do so, E1 assembles into a double-hexamer at the viral origin, unwinds DNA at the origin and ahead of the replication fork and interacts with cellular DNA replication factors. Biochemical and structural studies have revealed the assembly pathway of E1 at the origin and how the enzyme unwinds DNA using a spiral escalator mechanism. E1 is tightly regulated in vivo, in particular by post-translational modifications that restrict its accumulation in the nucleus. Here we review how different functional domains of E1 orchestrate viral DNA replication, with an emphasis on their interactions with substrate DNA, host DNA replication factors and modifying enzymes. These studies have made E1 one of the best characterized helicases and provided unique insights on how PVs usurp different host-cell machineries to replicate and amplify their genome in a tightly controlled manner.