UDP-GALACTOSE POLYSACCHARIDE TRANSFERASE IN THE CELLULAR SLIME MOLD, DICTYOSTELIUM DISCOIDEUM: APPEARANCE AND DISAPPEARANCE OF ACTIVITY DURING CELL DIFFERENTIATION

Abstract

UDP-galactose polysaccharide transferase activity was demonstrated in the cellular slime mold D. discoideum. It is absent in the vegetative cells and does not appear until relatively late in the developmental sequence, shortly before actual synthesis of a galactose-containing mucopolysaccharide. It reaches a peak of activity shortly before the end of fruiting-body con-struction and then disappears. Two morphogenetically deficient mutants which fail to synthesize the mucopolysaccharide (as well as many other morphological and biochemical end products) fail to display significant levels of enzyme activity at any time. A 3rd mutant, in which temporal control of morphogenesis has been altered, displays a consonant variation in the developmental kinetics of the transferase activity.