Polüadenüleerimine

Polüadenüleerimine is a biological process that occurs in eukaryotic cells. It refers to the addition of a tail of adenosine residues to the 3' end of messenger RNA (mRNA) molecules. This tail, known as the poly(A) tail, is not encoded in the DNA template but is added by an enzyme called poly(A) polymerase after transcription. The process of polyadenüleerimine is crucial for the maturation and stability of mRNA. The poly(A) tail protects the mRNA from degradation by cellular enzymes, thereby increasing its lifespan in the cytoplasm. It also plays a significant role in the export of mRNA from the nucleus to the cytoplasm, where protein synthesis takes place. Furthermore, the poly(A) tail is involved in the initiation of translation, the process by which ribosomes read the mRNA sequence to produce proteins. The length of the poly(A) tail can vary, and changes in its length can affect the efficiency of translation and the stability of the mRNA. This dynamic regulation of poly(A) tail length is an important mechanism for controlling gene expression. In some cases, abnormal polyadenüleerimine can lead to various cellular defects and diseases.