EARLY EXPRESSION OF A HATCHING ENZYME GENE IN MASU SALMON (ONCORHYNCHUS-MASOU) EMBRYOS

Hatching enzymes of fishes are developmentally regulated proteases sec reted from the hatching gland before hatching. We purified the hatchin g enzyme of masu salmon (Oncorhynchus masou) to one protein, determine d the N-terminal 19 amino acid sequence, and synthesized DNA in accord ance with this amino acid sequence. The developmental stage expressing the hatching enzyme gene was determined with Northern hybridization u sing this synthesized DNA as a probe. The hatching enzyme gene of masu salmon was expressed in the stage from the 20th to 28th days. Masu sa lmon embryos usually hatch out at the 40th day stage. Therefore, the h atching enzyme gene is expressed at an early stage before hatching.