Human Bocavirus 1 NP1 acts as an ssDNA-binding protein to help AAV2 DNA replication and cooperates with RPA to regulate AAV2 capsid expression.

Adeno-associated virus (AAV) requires co-infection with helper virus for efficient replication. We previously reported that Human Bocavirus 1 (HBoV1) genes, including NP1, NS2, and BocaSR, were critical for AAV2 replication. Here, we first demonstrate the essential roles of the NP1 protein in AAV2 DNA replication and protein expression. We show that NP1 binds to single-strand DNA (ssDNA) at least 30 nucleotides (nt) in length in a sequence-independent manner. Furthermore, NP1 colocalized with the BrdU-labeled AAV2 DNA replication center, and the loss of the ssDNA-binding ability of NP1 by site-directed mutation completely abolished AAV2 DNA replication. We used affinity-tagged NP1 protein to identify host cellular proteins associated with NP1 in cells cotransfected with the HBoV1 helper genes and AAV2 duplex genome. Of the identified proteins, we demonstrate that NP1 directly binds to the DBD-F domain of the RPA70 subunit with a high affinity through the residues 101-121. By reconstituting the heterotrimer protein RPA in vitro using gel filtration, we demonstrate that NP1 physically associates with RPA to form a heterologous complex characterized by typical fast-on/fast-off kinetics. Following a dominant-negative strategy, we found that NP1-RPA complex mainly plays a role in expressing AAV2 capsid protein by enhancing the transcriptional activity of the p40 promoter. Our study revealed a novel mechanism by which HBoV1 NP1 protein supports AAV2 DNA replication and capsid protein expression through its ssDNA-binding ability and direct interaction with RPA, respectively.IMPORTANCERecombinant adeno-associated virus (rAAV) vectors have been extensively used in clinical gene therapy strategies. However, a limitation of these gene therapy strategies is the efficient production of the required vectors, as AAV alone is replication-deficient in the host cells. HBoV1 provides the simplest AAV2 helper genes consisting of NP1, NS2, and BocaSR. An important question regarding the helper function of HBoV1 is whether it provides any direct function that supports AAV2 DNA replication and protein expression. Also of interest is how HBoV1 interplays with potential host factors to constitute a permissive environment for AAV2 replication. Our studies revealed that the multifunctional protein NP1 plays important roles in AAV2 DNA replication via its sequence-independent ssDNA-binding ability and in regulating AAV2 capsid protein expression by physically interacting with host protein RPA. Our findings present theoretical guidance for the future application of the HBoV1 helper genes in the rAAV vector production.

The COVID-19 pandemic and unemployment: Evidence from mobile phone data from China.

Based on mobile phone records for 71 million users and location tracking information for one million users over almost three years, this study examines the labor market impacts of the COVID-19 pandemic in China's Guangdong province, whose GDP is larger than that of all but the top 12 countries in the world. Using a standard difference-in-differences framework, our analysis shows dramatic and protracted effects of the pandemic on the labor market: it increased unemployment by 72% and unemployment benefits claims by 57% even after the full reopening in 2020 relative to their levels in the same period in 2019. The impact was also highly heterogeneous, with women, workers older than 40, and migrants being more affected. Cities that rely more on export or that have a higher share of the hospitality industry in GDP but a lower share of the finance and healthcare industries experienced a more pronounced increase in unemployment. The lingering impact likely reflects the global transmission of the pandemic's effects through the supply chain and trade channels.

The effectiveness and costs of nonpharmaceutical interventions for COVID-19 containment: A border discontinuous difference-in-difference approach.

We examine the effectiveness and costs of alternative nonpharmaceutical interventions (NPIs) for COVID-19 containment. Using a border discontinuous difference-in-difference approach, we find that the enforcement of rigid NPIs reduces the number of new COVID-19 cases by 10.8% in China, comparied with cities with less NPIs. Among the three NPIs, contact tracing is much more effective than the other two NPIs, namely, public information provision and social distancing. The connections of mayors to the upper-level politicians reinforce the city's implementation of rigid NPIs. These networks also serve as an informal signaling channel to the neighboring cities, encouraging the adjacent cities to impose strict NPIs to curb the spread of COVID-19. We further estimate the long-term costs of the NPIs - a net present value of 2153 yuan per child in the human capital loss attributed to more prolonged school closure alone.

Influence of clear cell carcinoma on the post-hepatectomy prognosis of patients with hepatocellular carcinoma.

Aim: The authors aimed to identify factors that independently influence the survival of patients with primary clear cell carcinoma of the liver (PCCCL). Methods: A total of 470 patients with hepatocellular carcinoma were retrospectively analyzed. Multivariate Cox analysis was used to identify potential factors associated with prognosis of PCCCL. Results: Patients with PCCCL showed significantly higher disease-free survival (DFS) and overall survival (OS) compared with patients with non-clear cell hepatocellular carcinoma. Multivariate analysis revealed that AFP level, tumor size, liver cirrhosis and portal vein tumor thrombosis were risk factors for DFS. Tumor size, capsule formation and Ki-67 were risk factors for OS. Satellite nodules acted as a protective factor for DFS and OS. Conclusion: PCCCL is associated with better prognosis in hepatocellular carcinoma. Tumor size and satellite nodules may be independent predictors of OS and DFS.

Magnetic Graphene Oxide-Fe3O4-PANI Nanoparticle Adsorbed Platinum Drugs as Drug Delivery Systems for Cancer Therapy.

Graphene-based magnetic nanoparticles (NPs) were synthesized using a simple and effective chemical precipitation method. To determine the biocompatibility of GO-Fe3O4-PANI NPs with MTT assay, cytotoxicity testing from a low concentration (1 µg/mL) to a high concentration (125 µg/mL) was conducted using various cancer and normal cell lines. Cytotoxicity testing for cancer cell lines (SMMC-7721, HepG-2, RAW264.7) and normal cell lines (HL-7702) showed almost no toxicity within the 1~125 µg/mL concentration range. Carboplatin (CBP) and oxaliplatin (OXP) were then used as drug models to study the drug release of CBP and OXP loaded on GO-Fe3O4-PANI NPs in vitro. Results indicated that the release of CBP and OXP from GO-Fe3O4-PANI NPs were affected by pH, dose, and temperature. The release of CBP was more sensitive to pH, and the amounts released in neutral and acidic environments (pH 6.0 and 7.4, respectively) were higher than those released in alkaline environments (pH 8.0). Meanwhile, at different pH levels, the release of OXP was not as large. In addition, at a low temperature (27 °C), the amount released is small when the energy level does not meet that required by C═N. At a considerably higher temperature (47 °C), the energy required for C═N fracture is met, allowing the slow release of the drug over a longer period. The results of our studies suggest that GO-Fe3O4-PANI NPs are biocompatible with MTT assay, and as drug delivery systems, these particular NPs can lead to advances in cancer treatment.

Fear of nuclear power? Evidence from Fukushima nuclear accident and land markets in China.

This paper examines whether the 2011 Fukushima Nuclear Accident (FNA) changed the Chinese public's attitude toward nuclear energy by studying transactions in land markets near nuclear power plants in China. Using a data set that matched the details of all nuclear reactors in China with information on land transactions around them before and after the FNA, we find that the accident had dynamic effects on land markets in China. Land prices within 40 km of nuclear power plants dropped by about 18% one month after the nuclear accident. However, the impact of FNA decreased over the longer term, eventually becoming statistically insignificant. Also, the impacts of the disaster varied with plant characteristics such as operating status, construction year, and size.