We report the constitution and molecular characterization of a novel transglutaminase (EC ) that starts to accumulate speci®cally in thenucleus in the star®sh (Asterina pectinifera) embryo after progression through the early blastula stage. The cDNA for the nuclear transglutaminase was clonedand the cDNA-deduced sequence de®nes a single open reading frame encoding aproteinwith737 aminoacids andapredictedmolecularmass of 83 kDa.