Project description:Post-transcriptional gene regulation controls the amount of a protein produced from an individual mRNA transcript by altering mRNA decay and translation rates. Many putative post-transcriptional cis-regulatory elements have been identified from computational, molecular biology, and biochemical studies studies; however, identifying which sequence elements are sufficient to regulate expression remains challenging. We created a high-throughput, cell-based screen that tested the post-transcriptional regulatory potential for thousands of short sequence elements. Sequences with known effects have the expected performance in this screen, showing this methodology is robust. Hundreds of novel short sequences were identified as being able to alter gene expression, both by increasing and decreasing protein production from the fluorescence reporter, and we validated the effects for fifty of these sequences. Importantly, sequences discovered in this screen are conserved in human 3′UTRs, and furthermore, the sequences can regulate expression in the context of those endogenous 3′UTRs. Hundreds of previously unknown post-transcriptional cis-regulatory elements exist, many of which increase gene expression. These results suggest that each human 3′UTR has many small cis-regulatory elements that interact with RNA binding proteins, and these interactions control the fate of an mRNA transcript.
Project description:Post-transcriptional gene regulation controls the amount of a protein produced from an individual mRNA transcript by altering mRNA decay and translation rates. Many putative post-transcriptional cis-regulatory elements have been identified from computational, molecular biology, and biochemical studies studies; however, identifying which sequence elements are sufficient to regulate expression remains challenging. We created a high-throughput, cell-based screen that tested the post-transcriptional regulatory potential for thousands of short sequence elements. Sequences with known effects have the expected performance in this screen, showing this methodology is robust. Hundreds of novel short sequences were identified as being able to alter gene expression, both by increasing and decreasing protein production from the fluorescence reporter, and we validated the effects for fifty of these sequences. Importantly, sequences discovered in this screen are conserved in human 3?UTRs, and furthermore, the sequences can regulate expression in the context of those endogenous 3?UTRs. Hundreds of previously unknown post-transcriptional cis-regulatory elements exist, many of which increase gene expression. These results suggest that each human 3?UTR has many small cis-regulatory elements that interact with RNA binding proteins, and these interactions control the fate of an mRNA transcript.
Project description:We present a combined experimental/computational technology to reveal a catalogue of functional regulatory elements embedded in 3’UTRs of human transcripts. We used a bidirectional reporter system coupled with flow cytometry and high-throughput sequencing to measure the effect of short, non-coding vertebrate-conserved RNA sequences on transcript stability and translation. Information-theoretic motif analysis of the resulting sequence-to-gene-expression mapping revealed linear and structural RNA cis-regulatory elements that positively and negatively modulate the post-transcriptional fates of human transcripts.
Project description:Evolutionary alterations to cis-regulatory sequences are likely to cause adaptive phenotypic complexity, through orchestrating changes in cellular proliferation, identity and communication. For non-model organisms with adaptive key-innovations, patterns of regulatory evolution have been predominantly limited to targeted sequence-based analyses. Chromatin-immunoprecipitation with high-throughput sequencing (ChIP-seq) is a technology that has only been used in genetic model systems and is a powerful experimental tool to screen for active cis-regulatory elements. Here, we show that it can also be used in ecological model systems and permits genome-wide functional exploration of cis-regulatory elements. As a proof of concept, we use ChIP-seq technology in adult fin tissue of the cichlid fish Oreochromis niloticus to map active promoter elements, as indicated by occupancy of trimethylated Histone H3 Lysine 4 (H3K4me3). The fact that cichlids are one of the most phenotypically diverse and species-rich families of vertebrates could make them a perfect model system for the further in-depth analysis of the evolution of transcriptional regulation. examination of H3K4me3 in adult fin tissue of the Nile tilapia (Oreochromis niloticus)
Project description:We performed chromatin immunoprecipitation (ChIP) followed by high-throughput sequencing (seq) from mouse E11.5 maxillary arches using anti-LHX6 antibody to identify LHX target cis-regulatory elements.
Project description:Transcriptional coregulators and transcription factors (TFs) contain intrinsically disordered regions (IDRs) that are critical for their partitioning and function in gene regulation. Canonically, IDRs drive coregulator-TF association by directly promoting multivalent protein-protein interactions. Using a chemical genetic approach, we report an unexpected mechanism by which the IDR of the corepressor LSD1 excludes TF association, acting as a dynamic conformational switch that tunes repression of active cis-regulatory elements. Hydrogen-deuterium exchange shows that the LSD1 IDR interconverts between transient open and closed conformational states, the latter of which inhibits partitioning of the proteins structured domains with TF hubs. This autoinhibitory switch controls leukemic differentiation by modulating repression of active cis-regulatory elements bound by LSD1 and master hematopoietic TFs. Together, these studies unveil that the dynamic crosstalk between opposing structured and unstructured regions is an alternative paradigm by which disordered regions can shape coregulator-transcription factor interactions to control cis-regulatory landscapes and cell fate.
Project description:Post-transcriptional regulation is crucial to shape gene expression. During the Maternal-to-Zygotic transition (MZT), thousands of maternal transcripts are regulated upon fertili-zation and genome activation. Transcript stability can be influenced by cis-elements and trans-factors, but how these inputs are integrated to determine the overall mRNA stability is unclear. Here, we show that most transcripts are under combinatorial regulation by multiple decay pathways. Characterization of the cis-regulatory motifs revealed that nu-cleotide composition bias characteristic of 3’-UTRs poly-U is associated with mRNA stability. In contrast, miR-430, CCUC, CUGC, elements appeared as the main destabiliz-ing motifs, with miR-430 and UAUUUAU (ARE) sequences causing mRNA deadenyla-tion depending on the activation of the genome. We comprehensively identify RNA-protein interactions across the transcriptome during MZT, and their associated regulatory activity. We find that poly-U binding proteins are preferentially associated with 3’-UTR sequences and stabilizing motifs. Analysis of differentially regulated regions revealed antagonistic sequence contexts for poly-C and poly-U binding proteins that shape protein binding and magnitude of regulation across the transcriptome. Finally, we integrate these regulatory motifs into a machine learning model, able to predict the stability of mRNA reporters in vivo. Our findings reveal how mechanisms of post-transcriptional regulation are coordinated to direct changes in mRNA stability within the early embryo.