Genes transcribe their encoded sequences as a RNA template that plays the role of precursor for messenger RNA (mRNA), being thus termed pre-mRNA. Messenger RNA is formed through the splicing of exons from pre-mRNA into a sequence of codons, ready for protein translation. Therefore, mRNA is also termed mature mRNA, because it can be transported to the cytoplasm, where protein translation will take place in the ribosomal complex.

Transcription occurs in the nucleus, through the following sequence of the events. The process of gene transcription into mRNA in the nucleus begins with the orginal DNA nitrogenous base sequence represented in the direction of transcription (e.g. from the 5' (five prime) end to the 3' (three prime end) as DNA 5'... AGG TCC TAG TAA...3' to the formation of pre-mRNA (for the exemplar DNA cited) with a sequence of 3'... TCC AGG ATC...