Eukaryotic translation factor 2 consists of three subunits alpha, beta, and gamma which are found in equal molar amounts in the cell. We are interested in studying the mechanism of regulation of these housekeeping genes. Northern analysis of the messages for the alpha and beta subunits revealed that the message for beta was five times more abundant than the message for alpha. An analysis of the translation efficiently showed that alpha message was translated more efficiently than the message for beta thus allowing the proteins to be present in equal molar amounts. This was confirmed by immunoprecipitation of pulse labeled proteins. In order to identify the element responsible for this differential translation full length message for both subunits were required. While a full length clone existed for alpha only a partial cDNA was available for beta, therefore we have undertaken the cloning of the beta. elF-2 beta is a single copy gene with at least four pseudogenes. The expressed gene spans more than 23 KB and is divided into 9 exons. By screening Lambda phage libraries, PCR generated libraries, and subgenomic libraries, we have cloned 23 KB of the loci representing 8 of the 9 exons. Several tries to clone the last exon which contains the 5' UTR and the promoter region have been unsuccessful. Due to the large size of the gene we are currently screening cosmid libraries in order to clone the 5' portion of the gene. By determining the mechanism(s) which control the differential translation of these two messages we may gain a better understanding of the effect of cis and trans elements regulating the efficiency of translation.
