Intron retention

Definition

Intron retention is a form of post-transcriptional regulation where introns, which are non-coding sequences of RNA, are retained in the mature mRNA instead of being spliced out. This process can lead to the production of multiple protein isoforms from a single gene, affecting gene expression and protein function. Intron retention can also play a role in regulating gene expression levels and is influenced by various cellular signals and conditions.

5 Must Know Facts For Your Next Test

1. Intron retention can result in the production of truncated proteins or proteins with altered functions, which can impact cellular processes.
2. It has been observed that intron retention can serve as a regulatory mechanism under stress conditions, allowing cells to adapt to changes in their environment.
3. Certain factors, such as RNA-binding proteins, can promote or inhibit intron retention by influencing the splicing machinery.
4. Intron retention is more prevalent in specific cell types and developmental stages, indicating its role in tissue-specific gene regulation.
5. Studies have shown that intron retention can contribute to disease mechanisms, including cancer, by altering gene expression profiles.

Review Questions

• How does intron retention contribute to the diversity of protein isoforms produced from a single gene?
  • Intron retention allows for the inclusion of non-coding sequences in mature mRNA, resulting in different protein isoforms being generated from a single gene. This process works alongside alternative splicing, enabling variations in protein structure and function. As a result, different isoforms can have distinct biological roles, thereby increasing functional diversity without the need for additional genes.
• Discuss the regulatory role of RNA-binding proteins in the process of intron retention and its implications for gene expression.
  • RNA-binding proteins play a crucial role in determining whether introns are retained or spliced out during mRNA processing. These proteins can interact with specific sequences within the pre-mRNA to either promote or inhibit intron retention. The balance between these opposing actions influences overall gene expression levels and can have significant implications for cellular responses to stress or developmental cues.
• Evaluate the significance of intron retention in disease mechanisms, particularly in cancer biology.
  • Intron retention has emerged as an important factor in cancer biology, as it can lead to altered protein expression profiles that contribute to tumor progression. The retention of certain introns may produce truncated or functionally distinct proteins that promote oncogenic pathways or enable cancer cells to evade apoptosis. Understanding how intron retention is regulated could provide insights into novel therapeutic strategies targeting aberrant splicing events associated with various cancers.

Related terms

Alternative splicing: A process during mRNA processing that allows for the generation of multiple protein isoforms from a single gene by including or excluding different exons and introns.

Spliceosome: A complex of proteins and RNA that is responsible for the removal of introns from pre-mRNA during the splicing process.

mRNA stability:

The measure of how long an mRNA molecule remains intact and functional within the cell, which can influence protein synthesis and degradation.