How is mRNA stability regulated in cells?

mRNA stability determines gene expression levels post-transcriptionally. Stabilizing elements include the 5' cap (protects from 5'-3' degradation), poly-A tail (protects from 3'-5' degradation), and specific sequences bound by stabilizing proteins. Destabilizing elements include AU-rich elements (AREs) in 3' UTR that recruit decay machinery, and nonsense-mediated decay (NMD) that eliminates transcripts with premature stop codons. MicroRNAs target mRNAs for degradation or translational repression. RNA-binding proteins (HuR, TTP) regulate stability in response to cellular signals. mRNA half-lives range from minutes to days, providing another layer of gene regulation.