Steely Enzymes Are Involved in Prestalk and Prespore Pattern Formation

4-Methyl-5-pentylbenzene-1,3-diol (MPBD), a product of SteelyA enzyme, controls <i>Dictyostelium</i> spore maturation. Since the expression of <i>stlA</i> split the in early and terminal stages, we cannot exclude the possibility that MPBD regulates spore differentiation from the early stage by creating a bias between the cells. 1-(3,5-Dichloro-2,6-dihydroxy-4-methoxyphenyl) hexan-1-on (DIF-1), a product of SteelyB, was identified as the major stalk cell inducer by <i>in vitro</i> assay, but <i>in vivo</i> assay revealed that DIF-1 induces only prestalkB (pstB) and prestalkO (pstO) cells and, that the major prestalkA (pstA) cells differentiated without DIF-1. In order to determine mechanism of polyketide regulated pattern formation, we examined the spatial expression patterns of prestalk and prespore markers in <i>stlA</i> and <i>stlB</i> knockout mutants. We found that MPBD regulates spore maturation at the culmination stage. We also found that the <i>stlA</i> and <i>stlB</i> double-knockout mutant lost pstA marker gene expression.