Study Notes on Non-coding RNAs

Overview of Non-coding RNAs

• Non-coding RNAs (ncRNAs) are RNA molecules that do not encode proteins, prevalent in most cell types.

• Historical focus in biology has been on proteins and DNA, but ncRNAs are crucial in many cellular processes.

Functions of ncRNAs

• Binding: ncRNAs bind to DNA/RNA, proteins, and small molecules, influencing DNA replication, transcription, and translation.

• Functions:

  • Scaffold: Bind multiple components to form complexes.

  • Guide: Direct proteins to specific locations.

  • Catalytic (Ribozyme): Catalyze biochemical reactions.

  • Blocker: Inhibit processes like translation.

  • Decoy: Sequester other ncRNAs.

Role in DNA Replication

• TERC (telomerase RNA component): Guides telomerase to telomeres to prevent chromosome shortening at replication ends.

Effects on Chromatin Structure & Transcription

• HOTAIR: Regulates gene expression through histone modification by binding protein complexes to silent target genes.

Translation and mRNA Degradation

• RNA Interference (RNAi): Initiated by double-stranded RNA is more effective than single-stranded.

• miRNAs and siRNAs: Play roles in gene regulation and response to exogenous RNA.

Protein Sorting

• Signal Recognition Particle (SRP): Directs protein localization, facilitated by SRP RNA functioning as a scaffold.

Genome Defense

• CRISPR-Cas System: Bacterial defense mechanism that uses ncRNA (tracrRNA) to target and cleave foreign DNA through a multi-step process.

Role in Human Disease and Plant Health

• ncRNAs are implicated in various diseases, including cancers and neurological disorders, and are vital for plant health and agriculture.