Fig 4.

Requirement of both ammonium permeases to form pseudohyphae in C. neoformans. (A) Wild-type cells and amt1 and amt2 single mutants were able to exhibit pseudohyphal growth on ¼ YNB media; however, amt1 amt2 double mutants were not able to undergo pseudohyphal growth. Scale = 10 μm. (B) Wild-type (WT), amt1, amt2, and amt1 amt2 progeny were obtained from a cross between congenic strains JR11 (amt1 amt2) and KN99a (wild type). Wild-type, amt1, and amt2 progeny exhibited pseudohyphal growth on ¼ YNB media, showing rough-edged, wrinkled colonies and invasive growth into the agar, whereas the amt1 amt2 double mutant formed smooth colonies with no pseudohyphae and less invasive growth into the agar. Scale = 5 μm.