Project description:Repeated parallel losses of inflexed stamens in Moraceae: phylogenomics and generic revision of the tribe Moreae and the reinstatement of the tribe Olmedieae (Moraceae)
Project description:Most current methods to identify cell-specific RNA binding protein (RBP) targets require analyzing an extract, a strategy that is problematic with small amounts of material. We previously addressed this issue by developing TRIBE, a method that expresses an RBP of interest fused to the catalytic domain (cd) of the RNA editing enzyme ADAR. TRIBE performs Adenosine-to-Inosine editing on candidate RNA targets of the RBP. However, target identification is limited by the efficiency of the ADARcd. Here we describe HyperTRIBE, which carries a previously characterized hyperactive mutation (E488Q) of the ADARcd. HyperTRIBE identifies dramatically more editing sites than TRIBE, many of which are also edited by TRIBE but at a much lower editing frequency. The data have mechanistic implications for the enhanced editing activity of the HyperADARcd as part of a RBP fusion protein and also indicate that HyperTRIBE more faithfully recapitulates the known binding specificity of its RBP than TRIBE.
Project description:RNA transcripts are bound and regulated by RNA-binding proteins (RBPs). Current methods for identifying in vivo targets of a RBP are imperfect and not amenable to examining small numbers of cells. To address these issues, we developed TRIBE (Targets of RNA-binding proteins Identified By Editing), a technique that couples an RBP to the catalytic domain of the Drosophila RNA editing enzyme ADAR and expresses the fusion protein in vivo. RBP targets are marked with novel RNA editing events and identified by sequencing RNA. We have used TRIBE to identify the targets of three RBPs (Hrp48, dFMR1 and NonA). TRIBE compares favorably to other methods, including CLIP, and we have identified RBP targets from as little as 150 specific fly neurons. TRIBE can be performed without an antibody and in small numbers of specific cells.
Project description:Aging is associated with the decline of protein, cell, and organ function. Here, we use an integrated approach to characterize gene expression, bulk translation, and cell biology in the brains and livers of young and old rats. We identify 468 differences in protein abundance between young and old animals. The majority are a consequence of altered translation output, that is, the combined effect of changes in transcript abundance and translation efficiency. In addition, we identify 130 proteins whose overall abundance remains unchanged but whose sub-cellular localization, phosphorylation state, or splice-form varies. While some protein-level differences appear to be a generic property of the rats’ chronological age, the majority are specific to one organ. These may be a consequence of the organ’s physiology or the chronological age of the cells within the tissue. Taken together, our study provides an initial view of the proteome at the molecular, sub-cellular, and organ level in young and old rats.
Project description:The genome is organized via CTCF/cohesin binding sites, which partition chromosomes into 1-5Mb topologically associated domains (TADs), and further into smaller contact sub-domains within TADs (sub-TADs; 40-1000kb). Here we examined in vivo an ~80kb sub-TAD, containing the mouse α-globin gene cluster, lying within a ~1Mb TAD. We find that the sub-TAD is flanked by predominantly convergent CTCF/cohesin sites which are ubiquitously bound by CTCF but only interact during erythropoiesis, defining a self-interacting erythroid compartment. Whereas the α-globin regulatory elements normally act solely on promoters downstream of the enhancers, removal of a conserved upstream CTCF/cohesin boundary extends the sub-TAD to the adjacent upstream CTCF/cohesin binding site. The α-globin enhancers now interact with the flanking chromatin, upregulating expression of genes within this extended sub-TAD. Rather than acting solely as a barrier to chromatin modification, CTCF/cohesin boundaries in this sub-TAD regulate both directionality and specificity of enhancer interactions with surrounding promoters.
Project description:The genome is organized via CTCF/cohesin binding sites, which partition chromosomes into 1-5Mb topologically associated domains (TADs), and further into smaller contact sub-domains within TADs (sub-TADs; 40-1000kb). Here we examined in vivo an ~80kb sub-TAD, containing the mouse α-globin gene cluster, lying within a ~1Mb TAD. We find that the sub-TAD is flanked by predominantly convergent CTCF/cohesin sites which are ubiquitously bound by CTCF but only interact during erythropoiesis, defining a self-interacting erythroid compartment. Whereas the α-globin regulatory elements normally act solely on promoters downstream of the enhancers, removal of a conserved upstream CTCF/cohesin boundary extends the sub-TAD to the adjacent upstream CTCF/cohesin binding site. The α-globin enhancers now interact with the flanking chromatin, upregulating expression of genes within this extended sub-TAD. Rather than acting solely as a barrier to chromatin modification, CTCF/cohesin boundaries in this sub-TAD regulate both directionality and specificity of enhancer interactions with surrounding promoters.
Project description:Streptococcus suis is a major pig pathogen as well as an emerging zoonotic pathogen. We studied the generic and adaptive resistance response of S. suis upon exposure to sub-lethal concentrations of the human cathelicidin LL-37. We aimed to search for inducible mechanisms of resistance to AMPs as well as induction of virulence gene expression upon exposure to AMPs, in order to gain insights into host-derived factors that might mediate S. suis pathogenesis.
Project description:Aging is associated with the decline of protein, cell, and organ function. Here, we use an integrated approach to characterize gene expression, bulk translation, and cell biology in the brains and livers of young and old rats. We identify 468 differences in protein abundance between young and old animals. The majority are a consequence of altered translation output, that is, the combined effect of changes in transcript abundance and translation efficiency. In addition, we identify 130 proteins whose overall abundance remains unchanged but whose sub-cellular localization, phosphorylation state, or splice-form varies. While some protein-level differences appear to be a generic property of the rats’ chronological age, the majority are specific to one organ. These may be a consequence of the organ’s physiology or the chronological age of the cells within the tissue. Taken together, our study provides an initial view of the proteome at the molecular, sub-cellular, and organ level in young and old rats. The corresponding dataset in Gene Expression Omnibus is <http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE66715">GSE66715</a>.