regulation of mRNA processing

Definition

Target type: biologicalprocess

Any process that modulates the frequency, rate or extent of mRNA processing, those processes involved in the conversion of a primary mRNA transcript into a mature mRNA prior to its translation into polypeptide. [GOC:ai]

mRNA processing, a critical step in gene expression, involves a complex series of events that regulate the synthesis of functional mRNAs from precursor mRNAs (pre-mRNAs). This intricate process is tightly controlled by a diverse array of factors, ensuring the precise production of mature mRNAs that can be translated into proteins. Key regulatory mechanisms include:

1. **Capping**: The 5' end of pre-mRNA is capped with a 7-methylguanosine (m7G) cap, a crucial modification that protects the mRNA from degradation and enhances translation initiation. Cap-binding proteins (CBPs) recognize the m7G cap and facilitate its interaction with ribosomes.

2. **Splicing**: In eukaryotes, pre-mRNAs typically contain non-coding introns that need to be removed before translation. Splicing is a highly regulated process that involves the precise excision of introns and the joining of exons, facilitated by the spliceosome, a complex macromolecular machine composed of snRNAs and proteins. Splicing can be alternative, meaning different combinations of exons can be used, generating multiple protein isoforms from a single gene.

3. **Polyadenylation**: The 3' end of pre-mRNA is cleaved and a poly(A) tail, a string of adenine nucleotides, is added. This tail protects the mRNA from degradation, enhances translation efficiency, and aids in mRNA export from the nucleus. Polyadenylation is regulated by polyadenylation factors that bind to specific sequences in the pre-mRNA.

4. **Nuclear Export**: Mature mRNAs are transported from the nucleus to the cytoplasm, where they are translated into proteins. This export is facilitated by nuclear pore complexes and requires specific mRNA export factors that recognize and bind to the mRNA.

5. **mRNA Stability**: The lifetime of an mRNA molecule influences its translation efficiency and the amount of protein produced. mRNA stability is regulated by a variety of factors, including:
* **5' cap**: The m7G cap protects the mRNA from degradation.
* **Poly(A) tail**: The poly(A) tail enhances mRNA stability.
* **Degradation signals**: Specific sequences in the mRNA can trigger degradation.
* **MicroRNAs (miRNAs)**: Small RNA molecules that can bind to mRNAs and regulate their stability.

6. **Translation**: The final stage of mRNA processing is translation, where the mRNA sequence is decoded into a protein sequence. This process involves ribosomes, transfer RNAs (tRNAs), and translation factors that work together to synthesize the polypeptide chain.

7. **Regulation by RNA Binding Proteins (RBPs)**: A wide range of RBPs interact with specific mRNA sequences, influencing various aspects of mRNA processing, including:
* **Splicing**: RBPs can modulate splice site selection, affecting the inclusion or exclusion of specific exons.
* **Polyadenylation**: RBPs can regulate polyadenylation site choice and the length of the poly(A) tail.
* **Nuclear Export**: RBPs can facilitate mRNA export from the nucleus.
* **mRNA Stability**: RBPs can influence mRNA stability by promoting or inhibiting degradation.
* **Translation**: RBPs can regulate translation initiation and efficiency.

In conclusion, mRNA processing is a highly regulated and dynamic process that ensures the faithful production of functional mRNAs. This complex regulatory network involves a diverse array of factors, including RNA-binding proteins, small RNAs, and enzymatic complexes, that control every step of the process, from capping and splicing to polyadenylation, nuclear export, stability, and translation. Understanding the intricacies of mRNA processing is essential for comprehending gene expression and its dysregulation in various diseases.'
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Proteins (8)

Compounds (170)