Biology subjects

Sanada, T.

Publications and source records attributed to Sanada, T..

4 recordsLinked to original sources

bioRxiv2026

Mouse oocytes organize mRNA-protein assemblies and ER-associated translation hubs to drive meiosis

Oocyte meiosis in animals is essential for producing fertilizable eggs. As transcription becomes largely quiescent, meiotic progression depends on temporally regulated translation of accumulated maternal mRNAs. However, the underlying mechanisms remain unclear. Here, we identified diverse and highly organized mRNA-protein assemblies in mouse oocytes that coordinate cytoplasmic mRNA regulation and enable spatiotemporal translation to drive oocyte meiosis. Twelve RNA-binding proteins (RBPs), including DDX4/VASA, HDLBP/Vigilin, and TDRD3, were assembled into widely distributed aggregates in germinal vesicle (GV)-stage oocytes. We depleted DDX4 and HDLBP using Trim-Away and found that these RBPs regulate the precise assembly of RNA granules and protein aggregates through distinct mechanisms, promoting temporal protein synthesis at cortical translation factories with the endoplasmic reticulum, termed CORTE. All 12 RBPs formed distinct mRNA-protein assemblies, whose size and distribution changed upon meiotic initiation. These findings reveal the molecular basis of spatiotemporal mRNA-protein-organelle networks underlying animal reproduction and development.

cell biology↗

bioRxiv2022

An attenuated vaccinia vaccine encoding the SARS-CoV-2 spike protein elicits broad and durable immune responses, and protects cynomolgus macaques and human ACE2 transgenic mice from SARS-CoV-2 and its variants

As long as the coronavirus disease 2019 (COVID-19) pandemic continues, new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with altered antigenicity will emerge. The development of vaccines that elicit robust, broad, and durable protection against SARS-CoV-2 variants is urgently needed. We have developed a vaccine (rDIs-S) consisting of the attenuated vaccinia virus DIs strain platform carrying the SARS-CoV-2 S gene. rDIs-S induced neutralizing antibody and T-lymphocyte responses in cynomolgus macaques and human angiotensin converting enzyme 2 (hACE2) transgenic mice, and showed broad protection against SARS-CoV-2 isolates ranging from the early-pandemic strain (WK-521) to the recent Omicron BA. 1 variant (TY38-839). Using a tandem mass tag (TMT) -based quantitative proteomic analysis of lung homogenates from hACE2 transgenic mice, we found that, among mice subjected to challenge infection with WK-521, vaccination with rDIs-S prevented protein expression related to the severe pathogenic effects of SARS-CoV-2 infection (tissue destruction, inflammation, coagulation, fibrosis, and angiogenesis) and restored protein expression related to immune responses (antigen presentation and cellular response to stress). Furthermore, long-term studies in mice showed that rDIs-S maintains S protein-specific antibody titers for at least 6 months after a 1st vaccination. Thus, rDIs-S appears to provide broad and durable protective immunity against SARS-CoV-2, including current and possibly future variants.

microbiology↗

bioRxiv2022

HBs-S antigen-dependent enhancement of HBV infection

Background AimsIn natural infections with hepatitis B virus (HBV), large amounts of hepatitis B surface-small antigen (HBs-S) subviral particles (SVPs), which do not contain viral nucleocapsid, are secreted into the blood. The function of excess amounts of SVPs remains largely unknown. In this study, we analyzed the function of HBs-S in HBV infection. MethodsThe effect of HBs-S in HBV infection was evaluated in a human hepatoma cell line, in primary human hepatocytes, and in chimeric mice with humanized livers. To analyze the involvement of glycosaminoglycan, HBs-S attachment to cells in the presence of heparin was evaluated by enzyme-linked immunosorbent assay (ELISA), and the enhancement of viral attachment was evaluated by measurement of viral DNA. Additionally, the interaction between HBs-S and viral particles was analyzed by immunoprecipitation. ResultsAttachment of the HBV DNA to cells inoculated with the combination of virus and HBs-S was significantly higher than that to cells inoculated with HBV only. Pretreatment of the cells with HBs-S also increased viral DNA levels significantly compared to that in untreated cells. In contrast, HBs-L did not enhance the viral attachment. Enhancement of viral attachment was associated with the attachment of HBs-S to the cells via heparan sulfate. HBs-S also interacted with the viral particle. Furthermore, in chimeric mice with humanized livers, HBs-S enhanced HBV infection. ConclusionsWe demonstrated that HBs-S enhances viral attachment in vitro and viral infection in vivo. HBs-S interacted with heparan sulfate on the cellular surface, and this interaction contributed to the enhancement of viral attachment. These data indicate that HBs-S enhances the viral infection, and may contribute to the high transmissibility of HBV.

microbiology↗

bioRxiv2020

Helicobacter small RNA regulates host adaptation and carcinogenesis

Type-1 carcinogenic Helicobacter pylori that is known to evolve during long-term infection, enters the stomach orally and causes gastric cancer using the carcinogenic protein CagA1. However, little is known about the adaptation mechanisms of H. pylori when the environment changes from the outside to the inside of the living body. Here we show that small non-coding RNA HPnc4160 is a crucial novel RNA molecule of H. pylori that negatively regulates bacterial-host adaptation and gastric cancer. H. pylori isolated from gerbils stomachs eight weeks post-infection acquired mutations in the increased number of T-repeats within the upstream region of the HPnc4160 coding region, which leads to reduced HPnc4160 expression levels that also seen in cancer patients-derived H. pylori. By comparing RNA-seq and iTRAQ analysis between wild-type and hpnc4160 deficient mutant strains, we identified eight targets of HPnc4160 including cagA and unknown factors. Mice infection experiment revealed that the hpnc4160 deficient mutant had a higher number of colonized bacteria in the mice stomach than the wild-type strain, indicating that reduced expression levels of HPnc4160 was important for bacterial host adaptation. The expression level of HPnc4160 was lower in the clinical isolates derived from gastric cancer patients compared with non-cancer-derived strains, while the mRNA expression levels of target factors were higher. Our findings highlight the first discovery that HPnc4160 is an important small RNA for bacteria to adapt to the host environment leading to gastric carcinogenesis.

microbiology↗