ABSTRACT: The human cellular nucleic acid binding protien binds G-rich elements close to translation initiation sires and promotes translation. [PAR-CLIP]
Project description:The human cellular nucleic acid binding protien binds G-rich elements close to translation initiation sires and promotes translation.
Project description:The human cellular nucleic acid binding protien binds G-rich elements close to translation initiation sires and promotes translation. [RNA-Seq]
Project description:CNBP is a eukaryote-conserved nucleic-acid binding protein required in mammals for embryonic development. It contains seven CCHC-type zinc-finger domains and was suggested to act as a nucleic acid chaperone, as well as a transcription factor. Here, we identify all CNBP isoforms as cytoplasmic messenger RNA (mRNA)-binding proteins. Using Photoactivatable Ribonucleoside Enhanced Cross-linking and Immunoprecipitation, we mapped its binding sites on RNA at nucleotide-level resolution on a genome-wide scale and find that CNBP interacted with 3961 mRNAs in human cell lines, preferentially at a G-rich motif close to the AUG start codon on mature mRNAs. Loss- and gain-of-function analyses coupled with system-wide RNA and protein quantification revealed that CNBP did not affect RNA abundance, but rather promoted translation of its targets. This is consistent with an RNA chaperone function of CNBP helping to resolve secondary structures, thus promoting translation. CNBP PAR-CLIP
Project description:DHX36 is a ATP-dependent, 3´-5´ RNA helicase of the DEAH family. Previous publications reported this helicase to associate with AU-rich elements and to specifically unwind G-quadruplex structures. Here, we performed PAR-CLIP in duplicates to specifically crosslink DHX36 and helicase-dead DHX36 E335A to its RNA binding targets in HEK293 cells. After sequencing and mapping to the human genome at nucleotide-resolution level we combined sequencing reads to a total of over 60000 binding clusters on more than 9000 transcripts. Distribution analyses revealed that DHX36 binds mainly to CDSs and 3´UTRS of mRNAs. Also, a G-rich binding motif for DHX36 was identified.
Project description:N6-methyladenosine (m6A) is a widespread internal RNA modification whose function is poorly understood. Here we report that m6A residues within the 5'UTR promote a novel form of cap-independent translation which is mediated through an interaction between m6A residues and the translation initiation factor, eIF3. We present eIF3a PAR-iCLIP data which demonstrate that eIF3 predominantly binds mRNAs within the 5'UTR. eIF3 binding sites are also in proximity to m6A residues within the 5'UTR of cellular mRNAs. Two replicates of eIF3a PAR-iCLIP in HEK293T cells.
Project description:PUF proteins have become a leading scaffold for designing RNA-binding proteins to contact and control RNAs at will. We analyze the effects of that reengineering across the transcriptome in vivo for the first time. We show, by HITS-CLIP and PAR-CLIP, that S. cerevisiae Puf2p, a non-canonical PUF protein, binds more than 1000 mRNA targets. Puf2p binds multiple UAAU elements, unlike canonical PUF proteins. We also perform CLIP-seq on truncations of the Puf2p, showing that its prion domain is dispensable for WT binding. We design a modified Puf2p to bind UAAG rather than UAAU, which allows us to align the protein with the binding site. In vivo, the redesigned protein binds UAAG sites. Its altered specificity redistributes the protein away from 3âUTRs, such that the protein tracks with its sites, binds throughout the mRNA. We use RNA-seq to determine that R1 SNE Puf2p represses a novel RNA network. CLIP-seq was performed in BY4742 S. cerevisiae grown in log phase, and using 2 replicates of TAP-tagged proteins.
Project description:Accumulating evidence suggests that posttranscriptional regulation of gene expression, including regulation of RNA splicing, transport, modification, translation, and degradation, primarily relies on RNA binding proteins (RBPs). However, the functions of many RBPs remain understudied. Here, we characterized the function of a novel RBP, Proline-Rich Coiled-coil 2B (PRRC2B). Through photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP) and deep sequencing, we identified transcriptome-wide CU- or GA-rich PRRC2B binding sites around the translation initiation codon on a specific cohort of mRNAs in HEK293T cells. These PRRC2B target mRNAs, including oncogenes and cell cycle regulators such as CCND2 (cyclin D2), exhibited decreased translation upon PRRC2B knockdown as revealed by sequencing polysome-associated RNA, resulting in decreased G1/S phase transition and cell proliferation. Antisense oligonucleotides (ASOs) blocking PRRC2B-CCND2 mRNA interaction decreased CCND2 translation, thus inhibited G1/S transition and cell proliferation. Mechanistically, PRRC2B interactome capture analysis revealed RNA-independent interactions with eukaryotic initiation factors eIF4G2, eIF3, and FXR1. The interaction with eIF4G2 is essential for PRRC2B function since unlike wildtype PRRC2B, eIF4G2-interacting defective mutants failed to rescue the translation deficiency caused by PRRC2B knockdown. Taken together, our findings reveal that PRRC2B, by interacting with eIF4G2, is essential for efficient translation of specific proteins required for cell cycle progression and cell proliferation.
