Gene expression encompasses all the processes by which the organization of chromosomal DNA is modified to affect its ability to undergo transcription, the transcription processes that generate nascent RNA molecules, the conversion of those RNAs to their mature forms, the translation of messenger RNAs (mRNAs) to generate nascent proteins, and the steps to convert those proteins to their mature forms. It also includes regulatory processes that affect the specificity and efficiency of each of these other processes, including the generation of non-coding RNAs and their effects on mRNA stability and translation.
In this Reactome superpathway, "Transcription", processes that modulate the ability of chromosomal DNA to undergo transcription and transcription by the three human RNA polymerases are annotated, as is mitochondrial transcription and relevant regulatory processes. Annotation of mRNAs by regulated RNA polymerase II (Pol II) transcription, including the assembly of transcription factor complexes and their role in targeting specific genes for transcription and Pol II mediated transcription itself.
Conversion of these RNA transcripts to their mature forms is annotated in the "Metabolism of RNA" superpathway.