RNA 7-methylguanosine cap binding

Definition

Target type: molecularfunction

Binding to a 7-methylguanosine group added cotranscriptionally to the 5' end of RNA molecules transcribed by polymerase II. [GOC:krc]

The 7-methylguanosine (m7G) cap is a unique modification found at the 5' end of eukaryotic messenger RNA (mRNA) molecules. It plays a critical role in the regulation of many fundamental cellular processes, including mRNA stability, translation initiation, and nuclear export. The m7G cap is recognized by a family of proteins known as cap-binding proteins (CBPs), which mediate its diverse functions.

The molecular function of RNA 7-methylguanosine cap binding can be described as follows:

1. **Recognition and Binding:** CBPs specifically recognize and bind to the m7G cap through a conserved cap-binding domain. This interaction is highly specific and provides a molecular basis for distinguishing mRNA from other cellular RNAs.

2. **Protection from Degradation:** The m7G cap protects the 5' end of mRNA from exonucleolytic degradation by 5' to 3' exonucleases. This protective function ensures the integrity and stability of mRNA molecules.

3. **Translation Initiation:** The m7G cap plays a crucial role in translation initiation. It is recognized by the eukaryotic initiation factor 4E (eIF4E), which is a key component of the translation initiation complex. Binding of eIF4E to the m7G cap facilitates the recruitment of the ribosome to the mRNA, thereby initiating protein synthesis.

4. **Nuclear Export:** The m7G cap is essential for the nuclear export of mRNA. It interacts with nuclear export factors, such as the cap-binding complex (CBC), which helps to transport mature mRNA from the nucleus to the cytoplasm, where it can be translated.

5. **mRNA Splicing:** The m7G cap has been implicated in mRNA splicing, the process by which non-coding introns are removed from pre-mRNA to produce mature mRNA.

6. **Regulation of Translation:** The m7G cap can influence the translation efficiency of specific mRNAs, depending on the presence of other regulatory elements within the mRNA sequence.

In summary, the molecular function of RNA 7-methylguanosine cap binding is multifaceted and essential for the proper regulation of gene expression in eukaryotic cells. It governs mRNA stability, translation initiation, nuclear export, and other critical cellular processes. This intricate molecular interaction ensures the efficient and accurate production of proteins from the genetic code.'
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Proteins (3)

Compounds (10)