Primary transcript

A primary transcript is the single-stranded ribonucleic acid (<a href="/facts/RNA/HxPeNfNj">RNA</a>) product synthesized by <a href="/facts/Transcription_(genetics)/bDgp9HDN">transcription</a> of <a href="/facts/DNA/nB89Iauz">DNA</a>, and processed to yield various mature RNA products such as <a href="/facts/MRNA/oUL6qxQn">mRNAs</a>, <a href="/facts/TRNA/pR9T5XSl">tRNAs</a>, and <a href="/facts/RRNA/zy5FxddY">rRNAs</a>. The primary transcripts designated to be mRNAs are modified in preparation for <a href="/facts/Translation_(biology)/JcPC1rth">translation</a>. For example, a precursor mRNA (pre-mRNA) is a type of primary transcript that becomes a messenger RNA (mRNA) after <a href="/facts/Post-transcriptional_modification/Hp9Ww9Nk">processing</a>.
Pre-mRNA is synthesized from a <a href="/facts/DNA/nB89Iauz">DNA</a> template in the <a href="/facts/Cell_nucleus/D7sFRa3c">cell nucleus</a> by <a href="/facts/Transcription_(genetics)/bDgp9HDN">transcription</a>. Pre-mRNA comprises the bulk of heterogeneous nuclear RNA (hnRNA). Once pre-mRNA has been completely <a href="/facts/Post-transcriptional_modification/Hp9Ww9Nk">processed</a>, it is termed "<a href="/facts/Mature_messenger_RNA/NrUDNQcC">mature messenger RNA</a>", or simply "<a href="/facts/Messenger_RNA/oUL6qxQn">messenger RNA</a>". The term hnRNA is often used as a synonym for pre-mRNA, although, in the strict sense, hnRNA may include nuclear RNA transcripts that do not end up as cytoplasmic mRNA.
There are several steps contributing to the production of primary transcripts. All these steps involve a series of interactions to initiate and complete the transcription of <a href="/facts/DNA/nB89Iauz">DNA</a> in the <a href="/facts/Cell_nucleus/D7sFRa3c">nucleus</a> of <a href="/facts/Eukaryotes/SkwyPLMA">eukaryotes</a>. Certain factors play key roles in the activation and inhibition of transcription, where they regulate primary transcript production. Transcription produces primary transcripts that are further modified by several processes. These processes include the <a href="/facts/Five-prime_cap/cWUeEBJ6">5' cap</a>, <a href="/facts/Polyadenylation/ILnXUBKP">3'-polyadenylation</a>, and <a href="/facts/Alternative_splicing/nNRwPVNK">alternative splicing</a>. In particular, alternative splicing directly contributes to the diversity of mRNA found in cells. The modifications of primary transcripts have been further studied in research seeking greater knowledge of the role and significance of these transcripts. Experimental studies based on molecular changes to primary transcripts and the processes before and after transcription have led to greater understanding of diseases involving primary transcripts.

Primary transcript open-in-new

Primary transcript