T.15 Modificación post-transcripcional del RNA: Splicing (títol)

RNA Splicing

Alternative Splicing

• A process that generates multiple mRNA isoforms from a single gene
• Involves the selection of different exons or exon segments to include in the final mRNA transcript
• Can result in different protein isoforms with distinct functions or localization
• Regulated by various factors, including:
  • Splicing factors (e.g. SR proteins, hnRNP proteins)
  • Chromatin modifications (e.g. histone modifications)
  • Transcriptional co-regulators (e.g. mediator complex)

RNA Editing

• A post-transcriptional modification that alters the nucleotide sequence of RNA
• Involves the deamination of specific nucleotides (e.g. A-to-I editing)
• Can affect the coding sequence, splicing patterns, or stability of the RNA molecule
• Enzymes involved: ADAR (adenosine deaminase acting on RNA) and APOBEC (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like)

mRNA Localization

• The process of targeting mRNA molecules to specific subcellular regions or organelles
• Involves the recognition of specific sequence elements (e.g. zip codes, localization elements) by RNA-binding proteins
• Regulated by various factors, including:
  • RNA-binding proteins (e.g. zipcode-binding protein 1)
  • Microtubules and microfilaments (cytoskeleton)
  • Signaling pathways (e.g. MAPK, mTOR)

RNA Transport

• The process of transporting RNA molecules from the nucleus to the cytoplasm
• Involves the recognition of specific sequence elements (e.g. nuclear export signals) by RNA-binding proteins
• Regulated by various factors, including:
  • Nuclear pore complexes
  • RNA-binding proteins (e.g. NXF1, Aly/REF)
  • Signaling pathways (e.g. CRM1, RanGTP)

Spliceosome

• A large ribonucleoprotein complex that catalyzes the removal of introns and joining of exons
• Composed of five small nuclear RNAs (snRNAs) and over 100 proteins
• The spliceosome recognizes specific sequence elements (e.g. splice sites, branch points) and catalyzes the splicing reaction
• Regulated by various factors, including:
  • Splicing factors (e.g. U1, U2, U4, U5, U6)
  • Chromatin modifications (e.g. histone modifications)
  • Transcriptional co-regulators (e.g. mediator complex)