A general upstream binding factor for genes of the yeast translational apparatus

Fractionation of yeast extracts on heparin-agarose revealed the presence of a DNA footprinting activity that interacted specifically with the 5'-upstream region of TEF1 and TEF2 genes coding for the protein synthesis elongation factor EF-1 alpha, and of the ribosomal protein gene RP51A. The protected regions encompassed the conserved sequences 'HOMOL1' (AACATC TA CG T A G CA) or RPG-box (ACCCATACATT TA) previously detected 200-400 bp upstream of most of the yeast ribosomal protein genes examined. Two types of protein-DNA complexes were separated by a gel electrophoresis retardation assay. Complex 1, formed on TEF1, TEF2 and RP51A 5'-flanking region, was correlated with the protection of a 25-bp sequence. Complex 2, formed on TEF2 or RP51A probes at higher protein concentrations, corresponded to an extended footprint of 35-40 bp. The migration characteristics of the protein-DNA complexes and competition experiments indicated that the same component(s) interacted with the three different promoters. It is suggested that this DNA factor(s) is required for activation and coordinated regulation of the whole family of genes coding for the translational apparatus.