Project description:Localization of RNase E to the inner membrane in Escherichia coli is well documented, but the functional consequences of this localization are largely unknown. Here we characterize the rne∆MTS strain, which expresses cytoplasmic RNase E (cRNase E). CsrB and CsrC regulatory RNAs are stabilized in the rne∆MTS strain resulting in leaky glycogen expression. There is a small but significant global slowdown in mRNA degradation with no bias considering function or localization of encoded proteins. RNase E is a stable protein, but cRNase E is unstable with a half-life equal to the doubling time of exponentially growing cells. cRNase E instability is compensated by increased synthesis. Co-purification experiments show that cRNase E associates with RhlB, enolase and PNPase to form a cytoplasmic RNA degradosome. Measurements in multiple turnover assays show that there is no difference in Km or kcat between cRNase E and RNase E. In contrast to the global slowdown of mRNA degradation, the inactivation of a ribosome-free lacZ transcript is faster in the rne∆MTS strain. We discuss how the association of RNase E with the inner cytoplasmic membrane is important for carbon storage regulation, degradation of polyribosomal mRNA, protection of ribosome-free transcripts from inactivation and stability of RNase E.
Project description:NAL1 (NARROW LEAF 1) is a breeding-valuable pleiotropic gene that affects multiple agronomic traits in rice, but the molecular mechanism is largely unclear. Here, we report that NAL1 is a serine protease and displays a novel hexameric structure whose formation is mediated by ATP-containing positively charged pocket at the N-terminal region. Moreover, we identified TOPLESS-related corepressor OsTPR2 involved in multiple growth and development processes as the substrate of NAL1. We found that NAL1 degraded OsTPR2, thus modulating the expression of downstream genes related to hormone signaling pathways, eventually achieving its pleiotropic physiological function. An elite allele NAL1A originated from wild rice could increase grain yield. Furthermore, the NAL1 homologs in different crops have a similar pleiotropic function to NAL1. Our study uncovers a NAL1-OsTPR2 regulatory module and provides gene resources for the design of high-yield crops.
Project description:Variation in gene expression arises from cis- and trans-regulatory mutations, which contribute differentially to expression divergence. Here, we compare the impacts on gene expression and fitness for cis- and trans-regulatory mutations affecting expression of the TDH3 gene in Saccharomyces cerevisiae. We use the effects of cis-regulatory mutations to isolate effects of trans-regulatory mutations caused by impacts on TDH3 from pleiotropic impacts on other genes, providing a rare distribution of pleiotropic effects. These pleiotropic effects were often, but not always, deleterious. For cis- and trans-regulatory mutations with similar effects on TDH3, trans-regulatory mutations had more widespread effects on gene expression, with distinct impacts on expression of genes downstream of TDH3. These differences between cis-and trans-regulatory mutations help explain their different contributions to regulatory evolution.
Project description:Genetic sharing is extensively observed for many autoimmune diseases, but the causal variants and their underlying molecular mechanisms remain largely unknown. Through systematic investigation of known autoimmune disease pleiotropic loci, we found that most of these genetic effects are transmitted from regulatory code and colocalize with hematopoietic lineage-specific expression quantitative trait loci. We used an evidence-based strategy to functionally prioritize known pleiotropic variants and identify their target genes. A top-ranked pleiotropic variant, rs4728142, yielded many lines of evidence as being causal, and regulates IRF5 transcript expression. Mechanistically, the rs4728142-containing region interacts with the IRF5 downstream alternative promoter in an allele-specific manner and orchestrates its upstream enhancer to regulate IRF5 alternative promoter usage through chromatin looping. A putative structural regulator, ZBTB3, mediates the allele-specific chromatin looping to promote IRF5 short transcript expression at the rs4728142 risk allele, resulting in IRF5 overactivation and M1 macrophage polarization. Together, our findings establish a causal mechanism between the regulatory variant and fine-scale molecular phenotype underlying the dysfunction of pleiotropic genes in human autoimmunity.
Project description:Abstract
Oxford Nanopore direct RNA sequencing (DRS) is capable of sequencing complete RNA molecules and accurately measuring gene and isoform expression. However, as DRS is designed to profile intact RNA, expression quantification may be more heavily dependent upon RNA integrity than alternate RNA-seq methodologies. It is currently unclear how RNA degradation impacts DRS or if it can be corrected for. To assess the impact of RNA integrity on DRS we performed a degradation time-series using SH-SY5Y neuroblastoma cells. Our results demonstrate that degradation is a significant and pervasive factor that can bias DRS measurements, including a reduction in library complexity resulting in an overrepresentation of short genes and isoforms. Degradation also biases differential expression analyses; however, we find explicit correction can almost fully recover meaningful biological signal. In addition, DRS provided less biased profiling of partially degraded samples than nanopore cDNA-PCR sequencing. Overall, we find samples with RIN > 9.5 can be treated as undegraded and samples with RIN > 7 can be utilised for DRS with appropriate correction. These results establish the suitability of DRS for a wide range of samples, including partially degraded in-vivo clinical and post-mortem samples, whilst limiting the confounding effect of degradation on expression quantification.
Project description:Cereblon (CRBN), a substrate receptor of the E3 ubiquitin ligase complex CRL4CRBN, is the target of the immunomodulatory drugs lenalidomide and pomalidomide. Recently, it was demonstrated that binding of these drugs to CRBN promotes the ubiquitination and subsequent degradation of two common substrates, transcription factors Aiolos and Ikaros. Here we report that the pleiotropic pathway modifier CC-122, a new chemical entity termed pleiotropic pathway modifier binds CRBN and promotes degradation of Aiolos and Ikaros in diffuse large B-cell lymphoma (DLBCL) and T cells in vitro, in vivo and in patients, resulting in both cell autonomous as well as immunostimulatory effects. In DLBCL cell lines, CC-122-induced degradation or shRNA mediated knockdown of Aiolos and Ikaros correlates with increased transcription of interferon stimulated genes (ISGs) independent of interferon α, β, γ production and/or secretion and results in apoptosis in both ABC and GCB-DLBCL cell lines. Our results provide mechanistic insight into the cell of origin independent anti-lymphoma activity of CC-122, in contrast to the ABC subtype selective activity of lenalidomide. Microarray analysis of the OCI-LY10 activated B-cell diffuse large B-cell lymphoma (ABC-DLBCL) cell line treated with the compound CC-122 for 18 hours