Microrna

Definition

Microrna (miRNA) is a small, non-coding RNA molecule, typically 21 to 25 nucleotides long, that plays a crucial role in regulating gene expression. By binding to complementary sequences on target messenger RNA (mRNA), miRNAs can inhibit translation or promote mRNA degradation, thereby influencing various biological processes such as development, differentiation, and stress responses.

5 Must Know Facts For Your Next Test

1. MiRNAs are involved in post-transcriptional regulation, meaning they act after the DNA has been transcribed into RNA, affecting how much protein is produced.
2. Each miRNA can target multiple mRNAs, and conversely, multiple miRNAs can regulate a single mRNA, creating a complex regulatory network.
3. The biogenesis of miRNAs involves several steps, including transcription from miRNA genes, processing by Drosha and Dicer enzymes, and incorporation into the RNA-induced silencing complex (RISC).
4. MiRNAs have been implicated in various diseases, including cancer, where they can act as oncogenes or tumor suppressors depending on their target mRNAs.
5. Research into miRNAs has led to their exploration as potential biomarkers for disease diagnosis and as therapeutic targets for innovative treatments.

Review Questions

• How do micrornas contribute to gene regulation in cells?
  • Micrornas contribute to gene regulation by binding to specific sequences on target messenger RNAs (mRNAs), leading to inhibition of translation or degradation of the mRNA. This post-transcriptional regulation allows cells to fine-tune protein production in response to various signals and conditions. The ability of a single miRNA to target multiple mRNAs adds an additional layer of complexity to gene expression regulation.
• What are the implications of altered microrna expression in diseases such as cancer?
  • Altered microrna expression can have significant implications in diseases like cancer. Depending on their target mRNAs, miRNAs can function as oncogenes or tumor suppressors. For example, when tumor-suppressing miRNAs are downregulated, it may lead to increased expression of oncogenes, promoting tumor growth and progression. Conversely, overexpression of certain miRNAs can inhibit the activity of tumor suppressor genes, further complicating cancer pathology.
• Evaluate the potential applications of microrna research in therapeutic interventions and disease diagnostics.
  • Research into micrornas has opened new avenues for therapeutic interventions and disease diagnostics. Since miRNAs play crucial roles in regulating gene expression linked to various diseases, they could serve as biomarkers for early detection and prognosis. Additionally, therapeutic strategies that aim to restore normal miRNA function or inhibit dysfunctional ones are being explored. Such strategies could provide targeted treatment options for conditions like cancer, cardiovascular diseases, and neurological disorders, potentially improving patient outcomes.

Related terms

mRNA: Messenger RNA (mRNA) is a type of RNA that conveys genetic information from DNA to the ribosome, where proteins are synthesized.

RNA interference: RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation by neutralizing targeted mRNA molecules.

Non-coding RNA: Non-coding RNA refers to RNA molecules that do not encode proteins but have regulatory roles in gene expression and cellular functions.