Final answer:
RNA-binding proteins and miRNAs bind to untranslated regions of mRNA to regulate post-transcriptional gene expression by affecting mRNA stability and localization, controlling the amount of protein translated from the mRNA. These interactions influence gene expression through epigenetic mechanisms and are vital in regulating eukaryotic gene expression.
Step-by-step explanation:
The noncoding regions known as untranslated regions (UTRs), bind to special protein molecules such as RNA-binding proteins (RBPs) and microRNAs (miRNAs), which play crucial roles in regulating gene expression post-transcriptionally. They control various aspects of the mRNA lifecycle that include mRNA localization, stability, and the translation process of protein synthesis. The 5' UTR and 3' UTR can bind with RBPs that either increase or decrease the stability of the mRNA molecule. This stability affects the amount of protein that will ultimately be translated from the mRNA.
These interactions are part of a larger epigenetic context, where protein and RNA interactions can affect gene expression through structural changes of the chromatin surrounding genes without altering the DNA itself.Furthermore, these regulatory mechanisms play a part in controlling whether eukaryotic cells express certain genes by directing the accessibility of DNA to RNA polymerase and associated transcription factors.
Chemical modifications such as methylation to histones or to the DNA itself can signal the cell to alter chromosomal regions to toggle gene expression on or off. After mRNA reaches the cytoplasm, translation control can also be exerted by binding to the ribosome and through elements like signal sequences that direct proteins to specific cellular destinations such as the endoplasmic reticulum. Therefore, the binding of proteins to noncoding regions is an intricate component of genetic regulation, affecting the functional output of genes in response to cellular demands and environmental cues.