Fig. 5. p42^POP is a Myb-like transcription factor. (A) Comparison of the p42^POP N-terminus with DBDs of Myb-related proteins. Bold characters indicate conserved residues indicative of the Myb repeat consensus. Sequences are from mouse (MM c-Myb: AAB59713, human (HS A-Myb: CAA57552, potato (MybSt1: AAB32591, Arabidopsis (AT MybL2: S71283), maize (ZM MYB1: S04898; ZM MYB38: S04899), barley (HV MYB1: P20026) and Drosophila (Zeste: P09956). (B) DNA-binding ability of p42^POP as revealed by EMSA. In-vitro-translated p42^POP was seen to bind to double-stranded [³²P]-labelled mreA oligodeoxynucleotides [left, without (-) and with (+) p42^POP]. (centre) Competition of complex formation by an identical unlabelled probe. (right) Control with a random DNA sequence. (C) The N-terminal fragment of p42^POP (N-POP) is sufficient for complex formation with mreA. Purified recombinant N-POP and the mutants N-POP-S25D and N-POP-R83E/W84P were incubated with the mreA sequence as described in (B). Whereas N-POP displays the electrophoretic shift indicating binding, single and double point mutations within the Myb-like repeat (asterisks in A) abolish this interaction. Arrows indicate the positions of the complexes.