The BAR1 gene results in secretion of a protease which degrades alpha factor.
It is phenotypically assayed on plates by placing the cells to be tested for
Bar phenotype between MATalpha cells secreting alpha factor and the MATa target
cells. Bar+ cells destroy the alpha factor and prevent MATa cells from
schmooing, while Bar- cells allow the schmooing to occur, as observed in the
microscope. Check cell type reviews or the original papers from the mid-1970's
(I can check if you have trouble).
Mike Leibowitz
RW Johnson Medical School
