Non-coding RNA

Definition

Non-coding RNA (ncRNA) refers to RNA molecules that do not translate into proteins but play critical roles in regulating gene expression and maintaining cellular functions. These molecules are essential for various biological processes, including transcription regulation, RNA splicing, and chromatin remodeling, making them vital players in the overall genetic landscape of organisms.

5 Must Know Facts For Your Next Test

1. Non-coding RNAs include various types such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and small nucleolar RNAs (snoRNAs), each having distinct functions.
2. During transcription initiation, certain non-coding RNAs can interact with transcription factors or the DNA template to influence gene expression levels.
3. Non-coding RNAs are involved in alternative splicing processes, which can create different protein isoforms from a single gene by varying the inclusion or exclusion of certain exons.
4. Some non-coding RNAs help in modifying chromatin structure, impacting how tightly DNA is packed and ultimately affecting gene accessibility for transcription.
5. The dysregulation of non-coding RNAs has been linked to various diseases, including cancer, by influencing pathways that control cell growth and differentiation.

Review Questions

• How do non-coding RNAs influence transcription initiation and what implications does this have for gene expression?
  • Non-coding RNAs influence transcription initiation by interacting with transcription factors or components of the transcription machinery. For instance, certain lncRNAs can recruit proteins that either activate or repress transcription at specific promoters. This modulation of transcription initiation is crucial as it determines whether genes are turned on or off, impacting overall gene expression profiles within the cell.
• Evaluate the roles of different types of non-coding RNAs in alternative splicing and chromatin remodeling.
  • Different types of non-coding RNAs play significant roles in both alternative splicing and chromatin remodeling. For example, small nuclear RNAs (snRNAs) are essential for the splicing process, helping to remove introns from pre-mRNA. Meanwhile, long non-coding RNAs can interact with chromatin modifiers to alter the structure of chromatin, making certain regions of DNA more or less accessible for transcription. These functions illustrate how non-coding RNAs are integral in regulating gene expression at multiple levels.
• Assess the impact of non-coding RNA dysregulation on cellular functions and disease progression.
  • The dysregulation of non-coding RNAs can severely impact cellular functions by disrupting normal gene expression patterns. For instance, altered levels of microRNAs can lead to insufficient suppression of oncogenes or excessive repression of tumor suppressor genes, contributing to cancer progression. Additionally, this dysregulation may affect pathways governing cell proliferation and differentiation, showcasing how non-coding RNAs are critical for maintaining cellular homeostasis and preventing disease.

Related terms

Messenger RNA (mRNA): A type of RNA that carries genetic information from DNA to the ribosome, where it is translated into a protein.

Ribosomal RNA (rRNA): A structural and functional component of ribosomes, playing a crucial role in protein synthesis.

Small interfering RNA (siRNA): Short, double-stranded RNA molecules that play a role in the RNA interference pathway, leading to the degradation of target mRNA.