Regulatie van expressie op meerdere niveaus

Cells precisely regulate gene expression during transcription, mRNA processing, and translation.

Transcriptional regulation can be mediated by proteins that bind regulatory sequences on DNA to inhibit or initiate the transcription of a specific gene.

Precursor mRNAs generated by transcription are modified by the addition of a 5-prime cap and a 3-prime poly-A tail. The mRNAs undergo splicing, where the non-coding regions are removed and the coding ones are joined to produce mature mRNAs. Differential splicing patterns and RNA-binding proteins regulate gene expression at this stage.

Only those mRNAs that associate with RNA-binding proteins to form ribonucleoprotein particles are selectively transported to the cytoplasm for translation.

Translational regulation can be specific, where inhibition of translation of a particular mRNA subset is controlled through interactions with proteins, microRNAs, and short-interfering or siRNAs.

In contrast, general translational regulation activates or inhibits proteins of the translation machinery to affect all transcripts.