STUDIES OF PROTEINS OF SEA URCHIN 

 EGG AND OF THEIR CHANGES 

 FOLLOWING FERTILIZATION 



ALBERTO MONROY: laboratory of comparative 



ANATOMY, THE UNIVERSITY OF PALERMO, ITALY 



The activation of the egg consists fundamentally in the release 

 of the metabolic reactions which are responsible for the initia- 

 tion of morphogenesis. To learn how this is accomplished is the 

 aim of the investigations of the physiological and biochemical 

 basis of morphogenesis. 



It therefore appears important to investigate the kind of 

 changes that take place in the various systems of the egg upon 

 fertilization since such analysis may help a great deal in under- 

 standing the basic mechanisms of the activation. The study of 

 the changes occurring in the proteins of the egg is obviously one 

 of the most interesting to pursue since it is at the protein level 

 that differentiation takes place and therefore it is hoped that it 

 may eventually help to uncover the basic events of differentiation. 



This study, although still at an early stage, indicates that im- 

 mediately following fertilization a process of rearrangement of 

 the whole protein pattern of the egg is started. On the other 

 hand, different lines of investigation give consistent evidence 

 that protein synthesis is started much later in development ( Perl- 

 mann and Gustafson, 1948; Perlmann, 1953; Hobermann, Metz, 

 and Graff, 1952; Hultin, 1953). 



The starting point for the study of the changes of the egg 

 proteins following fertilization was the observation of Mirsky 

 (1936) that in the sea urchin eggs a conspicuous decrease of 

 solubility of a protein fraction takes place during the first ten 

 minutes after fertilization, Mirsky showed, in fact, a 12% de- 



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