In vitro synthesis of T4 late messenger RNA.

Abstract
T4 late messenger RNA was synthesized in-vitro. In 1 of 3 in-vitro incorporation systems, late mRNA synthesis can be made dependent on the addition of a factor correlated with the functioning of T4 gene 55, a gene that also plays a role in controlling the expression of viral late genes in-vivo. This provides a direct in-vitro demonstration, at the level of transcription of the action of a control element of viral development.