Correction

CELL BIOLOGY. For the article “SEM1, a homologue of the split hand/split foot malformation candidate gene Dss1, regulates exocytosis and pseudohyphal differentiation in yeast” by Jussi Jäntti, Johanna Lahdenranta, Vesa M. Olkkonen, Hans Söderlund, and Sirkka Keränen, which appeared in number 3, February 2, 1999, of Proc. Natl. Acad. Sci. USA (96, 909–914), the authors note the following correction. In Results under the subheading “SEM1 Is Not Essential for Growth or Invertase Secretion,” the sentences “Disruption or deletion of SEM1 did not cause any obvious growth defects at different temperatures on synthetic or rich media containing different carbon sources. We conclude that SEM1 is a single-copy gene nonessential for growth,” should read “Disruption or deletion of SEM1 did not cause any obvious growth defects at different temperatures on synthetic or rich media. However, deletion of SEM1 caused poor growth on rich media when the sole carbon source was glycerol or galactose.”