Project description:Oncogenic translational programmes are an emerging hallmark of cancer and often driven by dysregulation of signaling pathways including KRAS and mTORC that converge on the eukaryotic translation initiation (eIF) 4F complex. Altered eIF4F activity promotes translation of oncogene mRNAs that typically contain highly structured 5’UTRs rendering their translation strongly dependent on RNA unwinding by DEAD-box helicase eIF4A1 subunit of the eIF4F complex. In addition, eIF4A1 separately functions to load mRNA into the 43S pre-initiation complex (PIC), an essential step for the translation of cellular mRNA. While eIF4A1-dependent mRNAs have been widely investigated, it is still unclear if highly structured mRNAs recruit and activate eIF4A1 unwinding specifically. Here, we uncover that unwinding by eIF4A1 is activated in an RNA sequence-dependent manner in cells. Our data demonstrate that eIF4A1-dependent mRNAs contain specific RNA sequences, particularly enriched for polypurine-motifs, in their 5’UTR which recruit and specifically stimulate unwinding of local repressive RNA structure by eIF4A1 in an RNA sequence-dependent manner to facilitate translation. Mechanistically, we show that polypurine-rich sequences trigger the formation of RNA sequence-specific multimeric eIF4A1-complexes, assembled of catalytically distinct eIF4A1 subunits, the joint activity of which enhances RNA unwinding activity. Together with our structural data, we describe a model in which conformational changes within eIF4A1 and the RNA through the process of eIF4A1 multimerisation, lead to an optimal interaction of eIF4A1-unwinding subunits with the structured RNA region which enhances unwinding. Hence, we conclude that RNA sequences in addition to protein cofactors contribute to the regulation of cellular eIF4A1 function and promotion of translation of eIF4A1-unwinding dependent mRNAs.
Project description:Mammalian-wide interspersed repeats (MIRs) are retrotransposed elements of mammalian genomes. Here we report the specific binding of zinc finger protein ZNF768 to the sequence motif GCTGTGTG (N20) CCTCTCTG in the core region of MIRs. ZNF768 binding is preferentially associated with euchromatin and promoter regions of genes. Binding was observed for genes expressed in a cell type-specific manner in human B cell line Raji and osteosarcoma U2OS cells. Mass spectrometric analysis of ZNF768 associated proteins revealed binding of ZNF768 to Elongator subunits 1, 2, and 3. The N-terminus of ZNF768 contains a heptad repeat array structurally related to the C-terminal domain (CTD) of RNA polymerase II. This array evolved in placental animals but not marsupials and monotreme species, displays species-specific length variations, and possibly fulfills CTD related functions in gene regulation. We propose that the evolution of MIRs and ZNF768 has extended the repertoire of gene regulatory mechanisms in mammals and that ZNF768 binding is associated with cell type-specific gene expression.
Project description:1. Evaluate the diagnostic value of long noncoding RNA (CCAT1) expression by RT-PCR in peripheral blood in colorectal cancer patients versus normal healthy control personal.
2. Evaluate the clinical utility of detecting long noncoding RNA (CCAT1) expression in diagnosis of colorectal cancer patients & its relation to tumor staging.
3. Evaluate the clinical utility of detecting long noncoding RNA (CCAT1) expression in precancerous colorectal diseases.
4. Compare long noncoding RNA (CCAT1) expression with traditional marker; carcinoembryonic antigen (CEA) and Carbohydrate antigen 19-9 (CA19-9) in diagnosis of colorectal cancer.
Project description:Pulmonary arterial hypertension (PAH) is a fatal disease characterized by a proliferative endothelial cell phenotype, inflammation and pulmonary vascular remodeling. BMPR2 loss-of-function has been linked to pathologic plexiform lesions with obliteration of distal pulmonary arteries distal pulmonary arteries BMPR2 silencing inprimary human pulmonary artery ECs (HPAECs) recapitulate important aspects of cellular dysfunction and deregulated signaling associated with PAH. Primary HPAECs were transfected with gene-specific siRNA pools targeting BMPR2 or control siRNA followed PMA or control stimulation.
Project description:Transcriptional profiling in HACAT cells using a whole human genome array; HACAT cells treated with si RNA against Keap 1 or a scrambled si RNA sequence (Scram) vs HACAT cells mock transfected with lipofectamine (reference control) Experiment Overall Design: 2 biological replicates, 2 technical (dye swap) replicates per treatment.
Project description:Dysregulation of miRs has been reported in a variety of cardiac diseases. In particular, it has reported that estrogen regulates a miRs network in female cardiac fibroblasts, thereby modulating a spectrum of genes involved in cardiac fibrosis and remodeling. However, the estrogen-responsive miRs in cardiomyocytes still remain to be elucidated. We used a microRNA microarray screening approach to address the miRs expression profiling in estrogen-treated cardiomyocytes.
Project description:High-throughput sequencing of Drosophila melanogaster small RNAs. total RNA, ~18-26nt RNAs isolated using PAGE, ligation to adapters requires 5' monophosphate and 3' OH Keywords: High-throughput solexa sequencing Small RNAs were sequenced from D. melanogaster female head. Raw sequences were clipped by 3' linker sequences recognition, and select clipped sequences longer than 18 nt Quality scores in the supplementary file for GSM240749 are undefined. Quality of the bases assessed by (1) identifying for the sequenced linker, which is a known sequence, and (2) mapping the clipped sequence to the genome and taking only perfect hits.