Genetic analysis of CHK1 and CHK2 homologues revealed a unique cross talk between ATM and ATR pathways in Neurospora crassa

Neurospora mrc1 homologue is involved in replication stability and is required for normal cell growth and chromosome integrity in mus-9 and mus-21 mutants

“…HU treatment induced phosphorylation of MUS-58 in the wild type, and phosphorylation was detected in the mrc1 mutant. In N. crassa, MUS-58 should mainly concern to the replication checkpoint, and MUS-59 only works as a sub-pathway for it (Wakabayashi et al, 2008). These results and the weak phenotype of the mrc1 mutant imply that mrc1 is not important for the replication checkpoint.…”

“…We then checked whether loss of spontaneous phosphorylation affects cell growth of the mrc1 mutant. In a previous study, we found that mus-9 and mus-21 mutants show characteristic growth defects: conidia from the mus-9 mutant have reduced viability and the mus-21 mutant exhibits slow hyphal growth (Wakabayashi et al, 2008). The mrc1 mus-9 and mrc1 mus-21 double mutants showed obviously reduced conidia viability and slow hyphal growth compared to those of the parental strains ( Fig.…”

“…We therefore checked whether N. crassa mrc1 is important for phosphorylation of MUS-58, which is a Chk1 homologue of N. crassa (Wakabayashi et al, 2008) (Fig. 2A).…”

“…Apical growth speed and colony formation rate were measured as described previously (Katou et al, 2003;Wakabayashi et al, 2008). The apical growth was measured from the origin of inoculation every 24 h by using race tubes.…”

ATM and ATR homologes of Neurospora crassa are essential for normal cell growth and maintenance of chromosome integrity

“…In N. crassa, we previously characterized mus-9 and mus-21 mutants, which are the ATR and ATM homologous genes, respectively (Kazama et al, 2007;Wakabayashi et al, 2008). The mus-9 mutant shows sensitivity to a wide variety of mutagens, while the sensitivity of the mus-21 mutant is restricted to several drugs that cause DSBs.…”