Figure 1.

DivL is a novel tyrosine kinase required for cell division and differentiation. (A) The 3,595-bp EcoRI/XhoI DNA fragment contains an ORF (open box) of 759 aa. R, EcoRI; No, NotI; Nc, NcoI; S, SstI; B, BamHI; P, PstI; and X, XhoI. (B) The conserved catalytic motifs, including the H- (Y- for DivL), N-, D-, and G-box, of the HPK superfamily (5), are for DivL and DivJ (22). An asterisk indicates the presumptive sites of autophosphorylation. (C) The replicating vector and hybrid plasmids encoding either wild-type [DivL (WT)] or mutant DivL proteins DivL^Y550F or DivL^Y550H (see text) were transferred by conjugation (25) to a recA-deficient strain carrying the temperature-sensitive divL346 allele. Cells were plated onto minimal medium at both 24°C and 37°C as indicated, and complementation was measured by colony-forming units. Numbers of colonies formed were normalized to 100% for DivL (WT).