The translation initiation factor eIF2 consists of three subunits that are present in equal molar amounts. The genomic DNA containing the gene for eIF2β and its promoter were cloned and sequenced to characterize further the mechanism of their regulated synthesis. Whereas Southern blot analysis indicated that a number of copies of the gene may exist, only one full- length intron-containing copy was identified. Similar to the eIF2α promoter, the eIF2β promoter is TATA-less, CAAT-less, and GC-rich and contains an α- Pal binding motif. Mutation of the α-Pal binding sequence resulted in an 8- fold decrease in activity when assayed by the luciferase reporter gene constructs. The data suggest a common mechanism of transcriptional control for the two cloned subunits of eIF2.
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