Disruption of the hup gene encoding a histone-like protein HS1 and detection of HS12 of Streptomyces lividans.

ABSTRACT

When the latter half of the hup gene encoding a histone-like protein HS1 of Streptomyces lividans TK24 was replaced by the kanamycin resistance gene, the hup mutant EY1 grew slowly in liquid medium and this delay was overcome by introduction of the complete hup. EY1 sporulated normally on solid medium, with no serious defects as observed in hupAB mutants of Escherichia coli. Therefore, HS1 probably has a role in growth in the presence of liquid medium and this organism may possess another histone-like protein with functions overlapping those of HS1. We cloned the hup2 gene encoding another histone-like protein HS12, which has two motifs of prokaryotic histone-like protein and eukaryotic histone H1. The amount of HS12 increased in EY1, determined by western blotting analysis using an anti-His-tagged HS12 polyclonal antibody. We are entertaining the notion that the increased amount of HS12 partially suppressed the defects caused by the hup mutation.