FIG. 5.

HUG1 and SML1 are transcribed independently, and deletions of either gene suppress mec1Δ lethality. The strains used were the wild type (W1588-4A) and the sml1-1 (YEF630), sml1Δ(U952-3C), and hug1Δ2 (YMB847) mutants. Transcription of SML1 was detected in logarithmically grown cells, whereas that of HUG1 was only detected in cells arrested with HU. The sml1-1 mutation (46) deletes a 290-bp region between two direct repeats of 11 bp; the first repeat is 7 bp downstream of the HUG1 stop codon. The sml1-1 mutation is present in most laboratory mec1 strains (25, 46).