The adenovirus tripartite leader sequence can alter nuclear and cytoplasmic metabolism of a non-adenovirus mRNA within infected cells.

All mRNAs encoded by the adenovirus major late transcription unit share a common 5' noncoding region, 200 nucleotides in length, termed the tripartite leader sequence. To assess function of the tripartite leader, recombinant viruses were prepared which carried either a bona fide herpes simplex virus thymidine kinase gene or a modified thymidine kinase gene whose normal 5' noncoding domain was replaced with the adenovirus leader sequence. The tripartite leader simultaneously decreased the nuclear half-life and increased the cytoplasmic half-life of the thymidine kinase-specific mRNA. The tripartite leader stabilized the non-adenovirus mRNA only within the environment of an adenovirus-infected cell during the late phase of the infectious cycle.