Amino terminus of the yeast GAL4 gene product is sufficient for nuclear localization.

Abstract

The intracellular compartmentalization in yeast [Saccharomyces cerevisiae] of Escherichia coli .beta.-galactosidase bearing heterologous amino acid sequences at its amino terminus were studied. Chimeras containing as few as 74 NH2-terminal amino acids of GAL4, a yeast positive regulatory protein, at the amino terminus accumulate in the cell nucleus. The GAL4 gene product may mediate positive control by binding to DNA; information for nuclear localization resides in its amino terminus. The amino acid sequence of the GAL4 amino terminus does not agree with the previously proposed consensus sequences responsible for nuclear localization. The .beta.-galactosidase activity in cells bearing the non-nuclear chimeric proteins is 10-fold greater than in cells bearing chimeric proteins that specifically concentrate in the nucleus.