Double-stranded DNA (deoxyribonucleic acid)
Single-stranded RNA (ribonucleic acid)
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Example 1: In humans, the 5’ capping of mRNA is essential for proper translation of genes involved in neuronal development. Mutations in the cap-binding proteins can lead to neurodevelopmental disorders.
Example 2: In viruses such as influenza, the viral RNA hijacks the cellular capping machinery to facilitate its own gene expression. This allows the virus to evade the host immune response and continue replicating.
Example 3: Bacterial mRNA molecules lack 5’ caps. Instead, they have unique structures called Shine-Dalgarno sequences that assist in translation initiation.
The type of cap modifications can influence translation efficiency.
For example, the presence of additional methyl groups on the cap structure can enhance translation initiation and increase protein synthesis rates.
Different cap-binding proteins, cap methyltransferases, and cap-binding complexes can affect translation rates and ultimately impact gene expression.
Mutations or disruptions in the components of the 5’ capping machinery can have severe consequences.
Loss of enzymes involved in the capping process can lead to a decrease in mRNA stability, impaired translation initiation, and aberrant gene expression.
Examples of diseases associated with 5’ capping defects include certain forms of cancer, neurodevelopmental disorders, and viral infections.
RNA-seq: Sequencing-based methods provide insights into the variety and abundance of mRNA molecules with different 5’ capping modifications.
Cap-Seq: Specifically designed to capture capped mRNA molecules, allowing for detailed analysis of the cap structure and its modifications.
Antibody-based techniques: Antibodies can be used to specifically visualize and isolate capped mRNA molecules, aiding in the study of translation initiation and regulation.
Continued research is needed to fully understand the biological significance of different cap modifications and their involvement in gene expression regulation.
Developing techniques to specifically manipulate and modify the cap structure may provide new possibilities for therapeutic interventions in various diseases.
Further exploration of the mechanisms involved in 5’ capping and translation initiation could lead to breakthroughs in our understanding of cellular processes and diseases.
5’ capping is a crucial post-transcriptional modification of mRNA.
It protects mRNA from degradation, enhances stability, and facilitates translation initiation.
The cap structure serves as a point of reference for ribosomes and helps in the identification of mRNA as “ready for translation”.
Defects in 5’ capping can lead to aberrations in gene expression and contribute to various diseases.
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Furuichi, Y., & Shatkin, A. J. (2000). Viral and cellular mRNA capping: Past and prospects. Advances in virus research, 55, 135–184. doi: 10.1016/S0065-3527(00)55004-X
Vazquez-Pianzola, P., Adamson, M. E., & Capraro, F. D. (2020). Distinct ribosome populations preferentially translate either early or late-occurring mRNAs in Drosophila melanogaster embryos. eLife, 9, e63184. doi: 10.7554/eLife.63184