Intron retention

Definition

Intron retention is a form of alternative splicing where introns, the non-coding sequences within a gene, are retained in the mature messenger RNA (mRNA) transcript instead of being spliced out. This phenomenon can result in the production of different protein isoforms and has implications for gene expression regulation, cellular function, and disease mechanisms.

5 Must Know Facts For Your Next Test

1. Intron retention can be a mechanism for generating protein diversity without the need for additional genes, allowing for functional flexibility.
2. This process may play a role in certain diseases, including cancer, where aberrant splicing patterns can lead to the production of proteins that promote tumorigenesis.
3. Intron retention is more commonly observed in certain cell types and developmental stages, indicating its potential role in cell-specific functions.
4. The presence of retained introns can influence mRNA stability and translation efficiency, ultimately affecting protein levels within the cell.
5. Recent studies have shown that intron retention may serve as a regulatory mechanism for modulating gene expression under stress conditions.

Review Questions

• How does intron retention differ from other forms of alternative splicing, and what are its potential functional consequences?
  • Intron retention differs from other forms of alternative splicing, such as exon skipping, because it specifically retains intronic sequences rather than excluding them. This can lead to the production of mRNA transcripts that may contain premature stop codons or alter protein structure and function. The functional consequences include generating diverse protein isoforms that can have distinct roles in cellular processes or contribute to disease mechanisms when splicing goes awry.
• Discuss the role of intron retention in the context of gene expression regulation and its implications for cellular function.
  • Intron retention plays a significant role in gene expression regulation by influencing mRNA stability and translation efficiency. Retained introns can affect the overall levels of protein produced from a gene by altering how long the mRNA remains intact before degradation or how effectively it is translated into protein. This has critical implications for cellular function, as different protein isoforms produced through intron retention may respond differently to cellular signals or stresses.
• Evaluate the impact of aberrant intron retention on disease mechanisms, particularly in cancer development.
  • Aberrant intron retention can have a profound impact on disease mechanisms, especially in cancer development. When intron retention occurs incorrectly, it can lead to the production of dysfunctional proteins that contribute to uncontrolled cell growth and survival. For example, specific retained introns may give rise to oncoproteins or inhibit tumor suppressor functions. Understanding these splicing abnormalities offers potential avenues for therapeutic interventions aimed at correcting or targeting these splicing events in cancer treatment.

Related terms

Alternative Splicing: A process by which different combinations of exons are joined together to create multiple mRNA transcripts from a single gene.

Exon Skipping: A type of alternative splicing where specific exons are excluded from the mature mRNA, leading to variations in the final protein product.

Gene Expression Regulation: The control of the timing and amount of gene expression, impacting how genes are turned on or off in response to various signals and conditions.