A p38a cDNA is expressed under the control of heat shock promoter.
Expression of two copies of P{hs-Mpk2.H} causes subnormal viability; 33.6% of control.
One copy of P{hs-Mpk2.H} rescues heat stress reponse defect of Mpk21 to 86.8% survival. However with two copies, survival falls back, to 75.4%.