RNATranskript

RNA transcript is an RNA molecule synthesized from a DNA template by RNA polymerase during transcription. Transcripts can be coding or noncoding, including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), and various small RNAs that regulate gene expression. The primary transcript is derived from a gene’s transcription unit and reflects the gene's sequence.

In most organisms, transcription begins at a promoter and proceeds through elongation until a termination signal. In eukaryotes, RNA polymerase II transcribes protein-coding genes and requires a set of transcription factors; the initial transcript, or pre-mRNA, undergoes processing before becoming mature mRNA. Processing in eukaryotes commonly includes addition of a 5' cap, splicing to remove introns, and a 3' poly(A) tail. Some transcripts undergo RNA editing or alternative splicing, increasing protein diversity. Prokaryotic transcription generally produces a primary transcript that can be immediately used in translation, and some transcripts are polycistronic.

Mature transcripts have distinct roles: mRNA provides the template for protein synthesis; rRNA and tRNA participate directly in ribosome function and translation; small noncoding RNAs regulate gene expression, RNA stability, and processing. The abundance and stability of transcripts influence gene expression and cellular responses.

Related topics include transcription regulation, RNA processing, RNA sequencing, and noncoding RNA biology.