Primary transcript

A primary transcript is the single-stranded ribonucleic acid (RNA) product synthesized by transcription of DNA, and processed to yield various mature RNA products such as mRNAs, tRNAs, and rRNAs. The primary transcripts designated to be mRNAs are modified in preparation for translation. For example, a precursor messenger RNA (pre-mRNA) is a type of primary transcript that becomes a messenger RNA (mRNA) after processing.

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 DNA in the nucleus of eukaryotes. 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 5' cap, 3'-polyadenylation, and alternative splicing. 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 the processes before and after transcription have led to greater understanding of diseases involving primary transcripts.

The steps contributing to the production of primary transcripts involve a series of molecular interactions that initiate transcription of DNA within a cell's nucleus. Based on the needs of a given cell, certain DNA sequences are transcribed to produce a variety of RNA products to be translated into functional proteins for cellular use. To initiate the transcription process in a cell's nucleus, DNA double helices are unwound and hydrogen bonds connecting compatible nucleic acids of DNA are broken to produce two unconnected single DNA strands. One strand of the DNA template is used for transcription of the single-stranded primary transcript mRNA. This DNA strand is bound by an RNA polymerase at the promoter region of the DNA.

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