This entry includes mediator of RNA polymerase II transcription subunit 16 (MED16; also known as SENSITIVE TO FREEZING 6 or SFR6) which is known only from plants. It is a component of the Mediator complex, which is required for transcription of almost all RNA polymerase II-dependent genes. Mediator provides an interface for activator and repressor proteins to transmit information from regulatory DNA elements to core promoters []. MED16 is a key component in acclimatization of plants to freezing temperatures [].
Mediator is a large complex of up to 33 proteins that is conserved from plants through fungi to humans - the number and representation of individual subunits varying with species [, ]. It is arranged into four different sections, a core, a head, a tail and a kinase-activity part, and the number of subunits within each of these is what varies with species. Overall, Mediator regulates the transcriptional activity of RNA polymerase II but it would appear that each of the four different sections has a slightly different function. Med16 is one of the subunits of the Tail portion of the Mediator complex and is required for lipopolysaccharide gene-expression []. Several members including the human protein, , have one or more WD40 domains on them.
