Structure, Processing, and Polymerization of Rainbow Trout Egg Vitelline Envelope Proteins

ABSTRACT The major vitelline envelope proteins were detected in the plasma of female rainbow trout maturing under natural conditions by using the Western blot technique. Females were sampled every month from July until ovulation in January. The amount of vitelline envelope proteins in plasma increased markedly as the gonads increased in size from 0·4 to about 15% of the total body weight. The plasma level of oestradiol-17β largely followed the alterations in the amount of vitelline envelope proteins, indicating the endocrine control of vitelline envelope protein synthesis. In addition, plasma vitellogenin changed in a manner that resembled the changes in the amount of plasma vitelline envelope proteins. The appearance and growth of the vitelline envelope during oocyte development was demonstrated using immunohistochemical methods. The vitelline envelopes from oocytes at different stages of development were immunoreactive with the antibodies directed against the major vitelline envelope proteins. No immunoreactivity could be observed in the ooplasm or in the surrounding follicular cells, which indicated that the major vitelline envelope proteins were of extraovarian origin. The present study further supports the hypothesis that the major protein constituents of the vitelline envelope in teleosts are under the endocrine control of oestradiol17β and that the site of synthesis is outside the ovary. Journal of Endocrinology (1992) 135, 303–309

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Oestradiol-17β induces the major vitelline envelope proteins in both sexes in teleosts

Journal of Endocrinology ◽

10.1677/joe.0.1310229 ◽

1991 ◽

Vol 131 (2) ◽

pp. 229-236 ◽

Cited By ~ 105

Author(s):

S. J. Hyllner ◽

D. O. Oppen-Berntsen ◽

J. V. Helvik ◽

B. T. Walther ◽

C. Haux

Keyword(s):

Rainbow Trout ◽

Amino Acid ◽

Brown Trout ◽

Polyclonal Antibodies ◽

Ovarian Follicle ◽

Envelope Proteins ◽

Structural Proteins ◽

Males And Females ◽

Vitelline Envelope ◽

Separate Class

ABSTRACT During growth of the ovarian follicle, the teleost oocyte becomes surrounded by an acellular coat, the vitelline envelope. The nature, origin and number of the vitelline envelope proteins in fish appear to vary with species. In this work, polyclonal antibodies directed against vitelline envelope proteins from rainbow trout, brown trout and turbot were used to show that oestradiol-17β induces the major vitelline envelope proteins in juveniles, both males and females, from different species. The fact that males can synthesize vitelline envelope constituents shows that the origin of these proteins is not confined to the ovary. The vitelline envelope of rainbow trout eggs consists of three major proteins, designated α (60 kDa), β (55 kDa) and γ (50 kDa). The amino acid composition of each of the three proteins indicated that the three proteins are alike and the suggestion that these proteins represent a separate class of structural proteins is sustained. Journal of Endocrinology (1991) 131, 229–236

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