THE ARREST OF EMBRYOGENESIS AT GASTRULA STAGE IN THE DIAPAUSING SILKWORM BOMBYX-MORI IS RELATED TO THE SYNTHESIS OF PROTEIN-P61

Two-dimensional protein gels are used to assess systematically changes in protein synthesis in diapausing and non-diapausing early embryos of Bombyx mori throughout natural breakage of diapause by chilling and after artificial prevention of diapause by HCl + heat-shock treatment. A set of proteins, the heat-shock protein (hsp) 70 family previously described, was synthesized in diapausing and non-diapausing development at the early germ-anlage stage; by contrast, protein 61 (P61; 61 kDa) was synthesized only in the diapausing gastrula stage. The synthesis of P61 decreased during days at 5-degrees-C. Thereafter, we observed the synthesis of the hsp 70 family at 5-degrees-C. After the artifical prevention of diapause, P61 synthesis was not induced at the gastrula stage, whereas the hsp 70 family was enhanced in the 6 h following the preventive treatment. P61 was only synthesized after treatments were ineffective in preventing diapause and in inducing hsp 70. Thus, P61 can be described as a "diapause arrest-associated protein."