Spliceosome

Definition

A spliceosome is a complex molecular machine in the cell that removes introns from a transcribed pre-mRNA. It performs RNA splicing to produce mature mRNA molecules ready for translation.

5 Must Know Facts For Your Next Test

1. Spliceosomes are composed of small nuclear RNAs (snRNAs) and protein complexes.
2. The core snRNAs involved in the spliceosome include U1, U2, U4, U5, and U6.
3. Spliceosomes recognize specific sequences at the intron-exon boundaries called splice sites.
4. Alternative splicing by spliceosomes allows for the generation of multiple protein variants from a single gene.
5. Mutations affecting spliceosome components can lead to various genetic diseases and cancers.

Review Questions

• What are the main components of a spliceosome?
• How does alternative splicing contribute to protein diversity?
• Which snRNAs are essential for the function of the spliceosome?

Related terms

Exon:

A segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.

Intron:

A non-coding segment of DNA or RNA that is removed during RNA splicing by the spliceosome.

RNA Polymerase II: An enzyme that synthesizes mRNA from a DNA template during transcription.