Cloning of cDNA and estrogen-induced hepatic gene expression for choriogenin H, a precursor protein of the fish egg envelope (chorion)

Abstract

A cDNA for choriogenin H (Chg H; formerly high-molecular weight spawning female-specific substances, or H-SF), a precursor protein of the inner layer subunits of egg envelope (chorion) of the teleost fish, Oryzias latipes, was cloned and analyzed. The clone consisted of 1913 bp and contained an open reading frame encoding a signal peptide of 22 aa and Chg H protein of 569 aa. The Chg protein possessed three potential N-glycosylation sites and Pro-X-Y repeat sequences in the first two-fifths of the N terminus. There were amino acid sequence similarities between Chg H and a gene product expressed in the liver of female winter f lounder during vitellogenesis. Moreover, the amino acid sequence of Chg H is similar to that of ZP2 rather than ZP3 of zona pellucida of some mammals. Northern blot analysis indicated that gene expression for Chg H occurred only in the livers of spawning female fish and 17␤-estradiol-treated male fish, but not in the ovary of the spawning female fish. Gene expression for Chg H and Chg L (formerly low-molecular weight spawning female-specific substance, or L-SF) was induced and increased in parallel in the male fish liver after 17␤-estradiol treatment.

Vitellogenesis and choriogenesis in fishes

“…Three Chg cDNAs that encode Chg H, Chg L and Chg H minor (Chg Hm) were cloned from the medaka liver, and their high homology to zona pellucida glycoprotein (ZP: ZPB and ZPC), which is synthesized in the mammalian ovary, was reported as well [106,107]. In addition, three genes encoding egg envelope proteins, zp1a, zp1b and zp3, were cloned from gilthead seabream Sparus aurata, and were reported to be highly expressed in the liver [108].…”

Expression and Localization of Eel Testicular ZP-homologues in Female Japanese Eels (Anguilla japonica)

“…In the latter teleosts, the egg envelope components are generally observed in females. These substances have also been detected in the serum of male teleosts after estradiol-17β treatment and their transcripts have been observed in the livers of such males (Hamazaki et al, 1987;Murata et al, 1991;Hyller et al, 1991;Oppen-Berntsen et al, 1992a,b ;Larsson et al, 1994;Murata et al, 1995Murata et al, , 1997Giacco et al, 1998a).…”

Sensitivities of mRNA Expression of Vitellogenin, Choriogenin and Estrogen Receptor by Estrogenic Chemicals in Medaka, Oryzias latipes.

“…The synthetic oligo-primer sequences used for RT-PCR of medaka Chg and ER were designed according to previously reported cDNA sequences. [9][10][11] To design suitable oligo-primers for VTG RT-PCR, partial cDNA fragments were isolated from the estrogen-treated medaka, then two cDNA clones were acquired (Fig. 1).…”

“…RT-PCR was carried out using a program temperature control system (Perkin Elmer 2400). The primers used for the RT-PCR of choriogenin (L: low molecular weight and H: high molecular weight), 9,10) estrogen receptor, 11) and β-actin, 12) were synthesized based on the previously known sequence. For the primers of vitellogenin I and II, partial sequencing of the cDNA was done in this study.…”