SUMMARY Embryonic stem cells (ESCs) repress the expression of exogenous proviruses and endogenous retroviruses (ERVs). Here, we systematically dissected the cellular factors involved in provirus repression in embryonic carcinomas (ECs) and ESCs by a genome-wide siRNA screen. Histone chaperones (Chaf1a/b), sumoylation factors (Sumo2/Ube2i/Sae1/Uba2/Senp6), and chromatin modifiers (Trim28/Eset/At-f7ip) are key determinants that establish provirus silencing. RNA-seq analysis uncovered the roles of Chaf1a/b and sumoylation modifiers in the repression of ERVs. ChIP-seq analysis demonstrates direct recruitment of Chaf1a and Sumo2 to ERVs. Chaf1a reinforces transcriptional repression via its interaction with members of the NuRD complex (Kdm1a, Hdac1/2) and Eset, while Sumo2 orchestrates the provirus repressive function of the canonical Zfp809/Trim28/Eset machinery by sumoylation of Trim28. Our study reports a genome-wide atlas of functional nodes that mediate proviral silencing in ESCs and illuminates the comprehensive, interconnected, and multi-layered genetic and epigenetic mechanisms by which ESCs repress retroviruses within the genome.

Changing scientific meetings for the better Conferences are a pivotal part of the scientific enterprise, but large in-person meetings have several disadvantages. As the pandemic experience has shown, online meetings are a viable alternative. Accelerating efforts to improve conferences in virtual formats can lead to a more equitable and sustainable conference culture.

Antimicrobial peptides (AMPs) are important components of the innate immune system of many species. These peptides are found in eukaryotes, including mammals, amphibians, insects and plants, as well as in prokaryotes. Other than having pathogen-lytic properties, these peptides have other activities like antitumor activity, mitogen activity, or they may act as signaling molecules. Their short length, fast and efficient action against microbes and low toxicity to mammals have made them potential candidates as peptide drugs. In many cases they are effective against pathogens that are resistant to conventional antibiotics. They can serve as natural templates for the design of novel antimicrobial drugs. Although there are vast amounts of data on natural AMPs, they are not available through one central resource. We have developed a comprehensive database (ANTIMIC, http://research.i2r. a-star.edu.sg/Templar/DB/ANTIMIC/) of known and putative AMPs, which contains approximately 1700 of these peptides. The database is integrated with tools to facilitate efficient extraction of data and their analysis at molecular level, as well as search for new AMPs. These tools include BLAST, PDB structure viewer and the Antimic profile module.

Scientific conferences provide valuable opportunities for researchers across career stages and disciplines to present their latest work and to network with their peers. The advent of the internet has opened new possibilities for interaction, collaboration and networking, yet the uptake of tools enabling remote participation at scientific meetings has been slow. Academic conferences have become more international with high proliferation in the number of meetings and attendees, but the format and quality of their organization lags behind what is possible. As a result, the experience of attending conferences in many disciplines today is not appreciably different in many respects. A few conferences in some disciplines have recently implemented valuable changes for the community and have become more receptive to attendees with families. Many meetings could still be improved significantly in terms of diversity, inclusivity, promoting early career researcher (ECR) networking and career development, venue accessibility, and more importantly, reducing the meetings' carbon footprint. These issues are openly visible and to some extent discussed among researchers on social media. It is important to accelerate and mandate these efforts so that researchers in all disciplines, in particular ECRs, consistently benefit from scientific gatherings, for years to come. We examined the current state of over 200 national and international academic meetings in various disciplines for key features of inclusivity and sustainability and propose solutions to make conferences more modern, effective, equitable and intellectually productive for the research community and environmentally sustainable for our planet.