Gene expression is dependent on two main types of signals, one involving transcription factors which initiates gene transcription, and another which regulates the translation of a nascent mRNA. These post-transcriptional events play an important yet incompletely understood role in regulating gene expression and cellular behavior. Many of the identified cis acting elements for translational regulation occur within the 3untranslated region (3 UTR), and some have been observed to occur with surprising regularity within certain protein function classes.