Chemistry of Life

Molecular genetics, biochemistry

RNA processing

Posttranscriptional RNA processing is an important feature of eukaryotic cells.

Pre-mRNA processing takes place in the nucleus. Introns are excised from the pre-mRNA transcript and the exons are ligated (spliced) to generate the mature mRNA. (left - click to enlarge image)

RNA processing events include capping of the 5’ end on the precursor mRNA, pre-mRNA splicing to remove intronic sequences, and polyadenylation of the 3’ end of the pre-mRNA.

Capping of the 5’ end of the nascent pre-mRNA is performed soon after initiation of transcription. Cleavage, pre-mRNA splicing, and polyadenylation usually follow termination of transcription of short primary transcripts with few introns. However, introns often are spliced out of the nascent RNA before transcription of the gene is complete for large genes with multiple introns. [] diagram - pre-mRNA processing Џ animation of RNA splicing : animation - mRNA processing : genetics animations [] diagram - spliceosome assembly :

NCBI Molecular Cell Biology : Post-transcriptional Processing of RNAs : Rediscovering Biology - Genomics Animations and Images - Genetics of Development - Animations and Images - Biology of Sex & Gender - Animations and Images - Genetically modified organisms - Animations and Images - Biodiversity - Animations and Images :

. . . transcription begun 10/06/06