Epigenetic Targeting of Adipocytes Inhibits High-Grade Serous Ovarian Cancer Cell Migration and Invasion.

Ovarian cancer (OC) cells frequently metastasize to the omentum, and adipocytes play a significant role in ovarian tumor progression. Therapeutic interventions targeting aberrant DNA methylation in ovarian tumors have shown promise in the clinic, but the effects of epigenetic therapy on the tumor microenvironment are understudied. Here, we examined the effect of adipocytes on OC cell behavior in culture and impact of targeting DNA methylation in adipocytes on OC metastasis.

Identification of Pol IV and RDR2-dependent precursors of 24 nt siRNAs guiding de novo DNA methylation in Arabidopsis.

In Arabidopsis thaliana, abundant 24 nucleotide small interfering RNAs (24 nt siRNA) guide the cytosine methylation and silencing of transposons and a subset of genes. 24 nt siRNA biogenesis requires nuclear RNA polymerase IV (Pol IV), RNA-dependent RNA polymerase 2 (RDR2) and DICER-like 3 (DCL3). However, siRNA precursors are mostly undefined.

Mapping RNA Sequences that Contact Viral Capsid Proteins in Virions.

We have adapted the methodology of CLIP-seq (Crosslinking-Immunoprecipitation and DNA Sequencing) to map the segments of encapsidated RNAs that contact the protein shells of virions. Results from the protocol report on the RNA sequences that contact the viral capsid.

A two-step process for epigenetic inheritance in Arabidopsis.

In Arabidopsis, multisubunit RNA polymerases IV and V orchestrate RNA-directed DNA methylation (RdDM) and transcriptional silencing, but what identifies the loci to be silenced is unclear. We show that heritable silent locus identity at a specific subset of RdDM targets requires HISTONE DEACETYLASE 6 (HDA6) acting upstream of Pol IV recruitment and siRNA biogenesis. At these loci, epigenetic memory conferring silent locus identity is erased in hda6 mutants such that restoration of HDA6 activity cannot restore siRNA biogenesis or silencing.

Prokaryotic Super Program Advisory Committee DOE Joint Genome Institute, Walnut Creek, CA, March 27, 2013.

The Prokaryotic Super Program Advisory Committee met on March 27, 2013 for their annual review the Prokaryotic Super Program at the DOE Joint Genome Institute. As is the case with any site visit or program review, the objective is to evaluate progress in meeting organizational objectives, provide feedback to from the user-community and to assist the JGI in formulating plans for the coming year. The advisors want to commend the JGI for its central role in developing new technologies and capabilities, and for catalyzing the formation of new collaborative user communities.

Community structure and functional gene profile of bacteria on healthy and diseased thalli of the red seaweed Delisea pulchra.

Disease is increasingly viewed as a major factor in the ecology of marine communities and its impact appears to be increasing with environmental change, such as global warming. The temperate macroalga Delisea pulchra bleaches in Southeast Australia during warm summer periods, a phenomenon which previous studies have indicated is caused by a temperature induced bacterial disease. In order to better understand the ecology of this disease, the bacterial communities associated with threes type of samples was investigated using 16S rRNA gene and environmental shotgun sequencing: 1) unbleached (healthy) D.

Geoarchaeota: a new candidate phylum in the Archaea from high-temperature acidic iron mats in Yellowstone National Park.

Geothermal systems in Yellowstone National Park (YNP) provide an outstanding opportunity to understand the origin and evolution of metabolic processes necessary for life in extreme environments including low pH, high temperature, low oxygen and elevated concentrations of reduced iron. Previous phylogenetic studies of acidic ferric iron mats from YNP have revealed considerable diversity of uncultivated and undescribed archaea. The goal of this study was to obtain replicate de novo genome assemblies for a dominant archaeal population inhabiting acidic iron-oxide mats in YNP.

Influence of nutrients and currents on the genomic composition of microbes across an upwelling mosaic.

Metagenomic data sets were generated from samples collected along a coastal to open ocean transect between Southern California Bight and California Current waters during a seasonal upwelling event, providing an opportunity to examine the impact of episodic pulses of cold nutrient-rich water into surface ocean microbial communities. The data set consists of ~5.8 million predicted proteins across seven sites, from three different size classes: 0.

Bacterial community assembly based on functional genes rather than species.

The principles underlying the assembly and structure of complex microbial communities are an issue of long-standing concern to the field of microbial ecology. We previously analyzed the community membership of bacterial communities associated with the green macroalga Ulva australis, and proposed a competitive lottery model for colonization of the algal surface in an attempt to explain the surprising lack of similarity in species composition across different algal samples. Here we extend the previous study by investigating the link between community structure and function in these communities, using metagenomic sequence analysis.

Functional genomic signatures of sponge bacteria reveal unique and shared features of symbiosis.

Sponges form close relationships with bacteria, and a remarkable phylogenetic diversity of yet-uncultured bacteria has been identified from sponges using molecular methods. In this study, we use a comparative metagenomic analysis of the bacterial community in the model sponge Cymbastela concentrica and in the surrounding seawater to identify previously unrecognized genomic signatures and functions for sponge bacteria. We observed a surprisingly large number of transposable insertion elements, a feature also observed in other symbiotic bacteria, as well as a set of predicted mechanisms that may defend the sponge community against the introduction of foreign DNA and hence contribute to its genetic resilience.

Catalytic promiscuity in the biosynthesis of cyclic peptide secondary metabolites in planktonic marine cyanobacteria.

Our understanding of secondary metabolite production in bacteria has been shaped primarily by studies of attached varieties such as symbionts, pathogens, and soil bacteria. Here we show that a strain of the single-celled, planktonic marine cyanobacterium Prochlorococcus-which conducts a sizable fraction of photosynthesis in the oceans-produces many cyclic, lanthionine-containing peptides (lantipeptides). Remarkably, in Prochlorococcus MIT9313 a single promiscuous enzyme transforms up to 29 different linear ribosomally synthesized peptides into a library of polycyclic, conformationally constrained products with highly diverse ring topologies.

Environmental genome shotgun sequencing of the Sargasso Sea.

We have applied "whole-genome shotgun sequencing" to microbial populations collected en masse on tangential flow and impact filters from seawater samples collected from the Sargasso Sea near Bermuda. A total of 1.045 billion base pairs of nonredundant sequence was generated, annotated, and analyzed to elucidate the gene content, diversity, and relative abundance of the organisms within these environmental samples.