Figure 1.

 The DdMYB2 locus and isolation of a Ddmyb2–null mutant. (A) REMI and gene targeting at DdMYB2 locus. W67 mutant was made by REMI of the BamH1-linearized plasmid pJB1 into the genome of uracil–auxothroph wild-type DH1 with the restriction enzyme DpnII. The DdMYB2 locus was isolated from genomic DNA using the restriction enzyme BglII. The Ddmyb2-null mutant was made by homologous recombination in wild-type AX3 genome with pMKO1, which contains a BSR, and pBluescript at the SacI site of the NheI–BglII genomic DNA fragment. The expected sizes of BglII fragments from wild-type cells and Ddmyb2 disruptant are indicated. (B) Southern analysis of the transformants with pMKO1. DNA was isolated from randomly picked transformants, digested with BglII, and probed with the SacI–BglII genomic fragment containing 3′ portion of DdMYB2 gene. MD255 was used as Ddmyb2 disruptant for further analysis. (C) Expression of DdMYB2 in wild-type AX3 and in Ddmyb2–null mutant MD255. RNA was prepared from either growing cells or cells that had been starved in suspension for the time indicated. The blot was probed with partial cDNA for DdMYB2 RNA (nucleotides 1675–1974 in Fig. 2B).