sev enhancers and an Hsp70 promoter drive expression of csw that has been mutated to carry the amino acid replacement R137K.
wild-type
cswR137K.hs.2sev rescues csw13-87
cswR137K.hs.2sev fails to rescue cswG547E.hs.2sev
Rescues the zygotic lethality of csw13-87/Y males. Also has maternal csw+ function; homozygous females carrying cswhs.2sev produce wild-type progeny.