An ARS/silencer binding factor also activates two ribosomal protein genes in yeast

GFI is an abundant yeast DNA-binding protein, capable of binding to both ARS sequences and to the upstream regions of a number of nuclear genes coding for mitochondrial proteins (Dorsman et al., Nucl. Acids Res., 16 [1988] 7287-7301). GFI binding sites conform to the consensus RTCRYN5ACG, an element also present in the binding sites of factors designated SUF and TAF. These factors act as trans-activators of the constitutive transcription of the genes for ribosomal proteins S33 and L3 respectively. We now present evidence that GFI, TAF and SUF are probably the same protein. We speculate that one of the functions of GFI is the adjustment of the expression of a number of gene families to cell growth rate.