Analysis of Brain mRNAs by Translation in Vitro

In vitro translation systems are extremely important tools for studying protein biosynthesis. These systems have been most useful in revealing the intracellular sites of synthesis of numerous proteins, the nature of cotranslational proteolytic cleavage events, the process of core glycosylation, and the mechanisms underlying the interaction of nascent polypeptides with organelles (such as mitochondria) and with membrane vesicles (rough microsomes, RM) derived from the rough endoplasmic reticulum (RER) (see Blobel, 1980 1 ; Sabatini et al., 1982, 9 for reviews). When programmed with the total mRNA from an organ, translation systems will synthesize virtually all the encoded polypeptides, and so can also be useful in identifying antigenically-related proteins. Although precipitating antibodies to the proteins under study have in the past been required for these analyses, it is now possible to synthesize from cloned cDNAs large quantities of individual mRNAs, that, when used to program an in vitro translation system, yield a single polypeptide that can be directly studied.