Amino acid permease genes were deleted in ura3 Sfl1Q320STOP (RB20) to obtain the mutants dip5 (RB317), gnp1 (RB197) and gap1 (RB531). Strains were grown one day on YPD at 30°C (A, upper panel) and washed to expose invasive growth (A, lower panel). FLO11 mRNA from individual mutants was examined by Northern blotting (B, upper panel) with 18S and 28S rRNA as loading controls (B, lower panel). Regulators of invasive growth were deleted in the RB20 background: flo11 (RB184), tec1 (RB540); tpk2 (RB538), cyr1 (RB201), gcn4 (RB475), mss11 (RB488), ssy1 (RB199) and ptr3 (RB486). After 3 days of growth on YPD (C), plates were flushed with water to reveal invasive growth (D). Mutant Sfl1Q320STOP strains in C and D are shown in E.