Five hundred spores were plated out on a complete medium (glucose 20 g L−1; MgSO4 2 mM; KH2PO4 3.4 mM; K2HPO4 5.7 mM; peptone 2 g L−1;

and yeast extract 2 g L−1, 1.5% agar) to assess whether antibiotic resistance and antibiotic sensitivity segregated 1 : 1. To this end, one hundred 1-day-old colonies were transferred to MM plates and grown for 2 days. The colonies were replicated on plates containing 20 μg mL−1 antibiotic (hygromycin or nourseothricin depending on the strain) and growth was monitored after 2 days. In the next step, antibiotic-sensitive and antibiotic-resistant siblings were selected that had mating types of strains H4-8 and H4-8b. To this end, siblings were crossed with these wild-type strains and clamp formation and fruiting body formation was monitored. Growth and fruiting body formation of dikaryons that contained Selleckchem Metformin a single- or a double-deleted ku80 gene was followed in time on MM plates and compared with that of a wild-type dikaryon. Spore formation was assessed Dasatinib chemical structure by growing the dikaryons on plates that had been placed inverted in the growth chamber and spore viability was checked by determining the CFUs of 100 spores. The phenotypes of the homozygous

monokaryotic and dikaryotic Δjmj3 and Δpri2 strains were assessed in a manner similar to that of the Δku80 strains. However, in this case, the ku80 gene was reintroduced before phenotypic analysis. To this end, a wild type was crossed with monokaryons in which jmj3 or pri2 had been HSP90 deleted (both types of deletion strains were nourseothricin and hygromycin resistant). Spores that were nourseothricin resistant, but hygromycin sensitive had a jmj3 or a pri2 deletion, but contained a wild-type ku80 gene. RNA isolation and qPCR were

performed as described (van Peer et al., 2009). After DNAse treatment, cDNA was synthesized using random hexamer primers and M-MuLV reverse transcriptase according to the manufacturer’s instructions (Fermentas; St. Leon-Rot, Germany). Real-time PCR was performed using the ABI Prism 7900HT SDS and SYBR Green chemistry (Applied Biosystems, Foster City, CA). Expression levels were related to that of the actin gene act1 (accession number AF156157). The levels of act1 and rad52 cDNA were determined using the primer pairs 5′-TGGTATCCTCACGTTGAAGTA-3′ and 5′-GTGTGGTGCCAGATCTT-3′ and 5′-GAAGAGTGGGCGGTTTA-3′ and 5′-CCTGCCCGTACCCAATA-3′, respectively. To inactivate the ku80 gene, S. commune monokaryon H4-8 was transformed with the deletion construct pKu80del. This vector consists of the hygromycin resistance cassette that is flanked by the up- and downstream regions of the coding sequence of ku80 and by a phleomycin resistance cassette that is positioned elsewhere in the vector. Six hundred hygromycin-resistant transformants were replicated on plates containing 5 μg mL−1 phleomycin.