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Most (almost all, AFAIK) mRNAs and lncRNAs start with exons for the reasons already mentioned by David. In a typical splicing event, the nucleotide that is 5' to the splice donor site (lets call it pre-donor) and the one that is 3' to the acceptor site (lets call it post acceptor) are joined together and the intronic sequence between them is removed. If ...


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Thank you for a great question. I would like to start by clarifying some terminology. First, nascent RNA refers to an RNA molecule that is currently being transcribed and has not been processed. Processing can include the splicing out of introns or polyadenylation at the 3' end, for example. Mature RNA is (typically) spliced and polyadenylated. Second, ...


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As far as I am aware, transcripts always start and end with exons. The reasons I wouldn’t expect otherwise (apart from my observations when examining Drosophila transcripts) are given below. As you will be aware, the spliceosome (at least for mRNA) is a highly sophisticated multi-component ribonuclear protein complex, and has functions to both splice out ...


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This is a deceptively and badly worded trick question. Your confusion is because it starts with a mention of RNA polymerase, which transcribes DNA into mRNA, but asks about the protein, which is produced by the translation of the mRNA on ribosomes. The first step in solving the problem is asking what is the sequence of the mRNA produced by the ...


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Concise Answer The 5′-UTR region of a eukaryotic mRNA is derived from the RNA transcript of the region of a gene between the transcription start site and the DNA corresponding to the translational initiation codon. It differs from that region of the initial transcript in most cases by having a modified guanosine nucleotide added at the 5′-end in a ‘cap’ ...


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Short answer The 5' UTR on the mRNA includes sequence from the Transcriptional Start Site (TSS) to the first exon. Promoters are usually associated with a corresponding TSS. Longer answer In defining a UTR we must consider where transcription begins. Strictly speaking transcription begins at the Transcriptional Start Site (TSS). A useful website for exact ...


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The UTR is the region of the transcript upstream of the starting methionine. The promotor is not itself transcribed.


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As Shigeta mentioned, transcription factors are proteins that regulate gene expression which can be either positive (activation) or negative (repression). Sometimes the same transcription factor can act as a repressor or an activator under different conditions. Transcription factors have specific target genes. General transcription factors (GTF), however ...


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Activators turn genes on - they help or promote RNA transcription of the gene. Other Transcription factors may turn genes off (prevent or reduce RNA transcription). Some transcription factors may promote or inhibit RNA transcription depending on their environment/context. Transcription factors is such a generic term that anything can happen in practice. ...



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