Salmon Eggshell Protein Expression: A Marker for Environmental Estrogens

Abstract

: A liver complementary DNA expression library from Atlantic salmon (Salmo salar) pretreated with estradiol-17beta (E2) was constructed and screened with antibodies raised against salmon eggshell (zona radiata) proteins. Two clones, SalZr2_19 and SalZr2_23 were sequenced and shown to encode proteins of approximately 50 kDa. SalZr2_23 contains 12 octamer sequence lpqr/kpa/vq repeats also found in SalZr2_19, but only twice. Alignment reveals that the two salmon sequences are similar to piscine zona radiata proteins and mammalian zona pellucida proteins. Several transcripts ranging from 2.3 to 12 kb appeared in liver extracts of E2-treated fish. Juvenile fish treated with E2 or 4-nonylphenol showed strong induction of zona radiata protein. The use of egg envelope transcriptional and translational induction in male or juvenile fish as a biological marker of environmental estrogens is discussed.

Histological and immunohistochemical investigation on ovarian development and plasma estradiol levels in the swordfish (Xiphias gladius L.)

“…The discrepancy observed in the ZR reactivity to Pas and abSal-Zrp during follicle growth may depend on the lacking of exogenous Zrp in oocytes with diameter < 180 µm as well as on the low sensitivity of the eterologous antibody used. The immunohistochemical findings, at least, can be considered reliable because Zrp is structurally conserved among teleostean fish (Oppen-Berntsen et al, 1999). In addition, as reported in the product specification sheet, the antibody used cross-reacts well with Zrp from different teleosts, including Perciformes species.…”

Oocyte zona pellucida proteins

“…Salmonid species Modig et al (2006) E 2 , 17β-estradiol;EE 2 , 17α-ethinylestradiol;11-KT, 11-ketotestosterone. have been used as sentinels for the presence of estrogenic substances in water. The induction of Vtg is predominantly used as a biomarker, although recently the use of ZP proteins has been suggested as an alternative indicator for estrogenic endocrine-disrupting substances (Arukwe et al, 1997(Arukwe et al, , 2001(Arukwe et al, , 2002Celius and Walther, 1998;Celius et al, 1999;Oppen-Berntsen et al, 1999).…”

Cloning of Rainbow Trout Egg Envelope Proteins: Members of a Unique Group of Structural Proteins1

“…To date, teleost VEP nucleotide sequences and deduced protein sequences have been obtained from winter flounder [17], Japanese medaka [18][19][20], carp [21,22], goldfish [22], Atlantic salmon [23], and zebrafish [24]. So far, characterization of all the VEP isoforms, which correspond to the mammalian ZP1, ZP2, and ZP3, has only been reported for one teleost species, the Japanese medaka.…”