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🔬general biology i review

Cleavage stimulatory factor (CstF)

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Cleavage stimulatory factor (CstF) is a multi-protein complex that plays a critical role in the process of mRNA cleavage and polyadenylation during eukaryotic transcription. CstF is essential for the proper cleavage of pre-mRNA at the polyadenylation site, ensuring the stability and maturation of the resulting mRNA molecules. By facilitating the addition of a poly(A) tail, CstF helps to enhance mRNA stability, nuclear export, and translation efficiency.

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5 Must Know Facts For Your Next Test

  1. CstF is composed of multiple subunits that work together to recognize specific RNA sequences at the cleavage site.
  2. The binding of CstF to the pre-mRNA occurs after the recognition of the polyadenylation signal by CPSF.
  3. CstF not only promotes cleavage but also plays a role in recruiting other factors necessary for mRNA processing.
  4. Dysfunction or mutations in CstF can lead to improper mRNA processing, which may result in various diseases or developmental issues.
  5. CstF's activity is regulated by phosphorylation and other post-translational modifications, affecting its interaction with pre-mRNA.

Review Questions

  • How does Cleavage stimulatory factor (CstF) interact with other protein complexes during mRNA processing?
    • CstF interacts primarily with Cleavage and Polyadenylation Specificity Factor (CPSF) during mRNA processing. After CPSF recognizes the polyadenylation signal on pre-mRNA, CstF binds to the RNA downstream of this signal. Together, these complexes coordinate the cleavage event at the polyadenylation site, ensuring that pre-mRNA is properly processed into mature mRNA ready for translation.
  • What are some potential consequences of dysfunction in Cleavage stimulatory factor (CstF) for gene expression?
    • Dysfunction in CstF can lead to improper cleavage and polyadenylation of pre-mRNAs, resulting in unstable or dysfunctional mRNAs. This can ultimately affect gene expression levels, potentially leading to decreased protein production or the production of truncated proteins that may disrupt normal cellular functions. Such alterations can contribute to diseases, including cancer and genetic disorders.
  • Evaluate how understanding the role of Cleavage stimulatory factor (CstF) can influence therapeutic strategies in treating diseases associated with gene expression abnormalities.
    • Understanding the role of CstF in mRNA processing provides insights into potential therapeutic targets for diseases linked to gene expression abnormalities. For example, if specific mutations in CstF or its regulatory pathways are identified as contributors to certain cancers or genetic disorders, therapies could be designed to correct or compensate for these defects. Targeting CstF interactions or enhancing its function might improve mRNA processing outcomes, leading to more effective treatments and a better understanding of how gene expression impacts health.