Expression of perivitelline membrane glycoprotein ZP1 in the liver of Japanese quail (Coturnix japonica) after in vivo treatment with diethylstilbestrol.
ABSTRACT Avian perivitelline membrane, an oocyte extracellular matrix homologous to the zona pellucida in mammals or chorion in fish, is composed of at least two glycoproteins. Previous studies have indicated that one of the components, a glycoprotein homologous to mammalian ZPC, is produced in the granulosa cells of the developing follicles of quail ovary on stimulation with testosterone. However, little is known about the molecular biology of the other component of the avian perivitelline membrane, ZP1, and information about gene expression is particularly lacking. We have cloned the ZP1 in Japanese quail and examined its gene expression. A cDNA encoding quail ZP1 was isolated from the livers of mature females using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends. It encoded a 934-amino acid protein that showed greatest homology (87.8% identity) with the chicken ZP1. RT-PCR amplification indicated that the ZP1 mRNA in the liver was restricted to mature laying females. The expression of ZP1 mRNA was stimulated by in vivo treatment with diethylstilbestrol in immature females as well as males. These results suggested that androgens and estrogens coordinately regulate the formation of quail perivitelline membrane proteins. In addition, the use of ZP1 transcriptional induction in males or immature females as a biological marker of environmental estrogens is discussed.
Article: Can ovarian follicles fossilize?[Show abstract] [Hide abstract]
ABSTRACT: ARISING FROM X. Zheng et al. 495, 507-511(2013)In a recent report Zheng et al. describe ovarian follicles in three fossil birds from the Early Cretaceous period of China belonging to Jeholornis and two enantiornithine species. Because these were situated in the left half of the body cavity of the fossils, the authors suppose that the right ovary was already reduced in these early birds. Fossilization of ovarian follicles would constitute an extraordinary case of soft tissue preservation, but the morphology of the fossil structures does not agree with the ovulation mode of coelurosaurs. There is a Reply to this Brief Communication Arising by O'Connor, J., Zheng, X. & Zhou, Z. Nature 499, http://dx.doi.org/10.1038/nature12368 (2013).Nature 07/2013; 499(7457):E1. · 38.60 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: At the time of fertilization, the extracellular matrix surrounding avian oocytes, termed the perivitelline membrane (pvm), is hydrolyzed by a sperm-borne protease, although the actual protease that is responsible for the digestion of the pvm remains to be identified. Here, we show evidence that the ubiquitin-proteasome system is functional in the fertilization of Japanese quail. The activities for the induction of the acrosome reaction and binding to ZP3 as revealed by ligand blotting of purified serum ZP1 are similar to those of pvm ZP1. Western blot analysis of purified ZP1 and ZP3 by the use of the anti-ubiquitin antibody showed that only pvm ZP1 was reactive to the antibody. In vitro penetration assay of the sperm on the pvm indicated that fragments of ZP1 and intact ZP3 were released from the pvm. Western blot analysis using the anti-20S proteasome antibody and ultrastructural analysis showed that immunoreactive proteasome was localized in the acrosomal region of the sperm. Inclusion of specific proteasome inhibitor MG132 in the incubation mixture, or depletion of extracellular ATP by the addition of apyrase, efficiently suppressed the sperm perforation of the pvm. These results demonstrate for the first time that the sperm proteasome is important for fertilization in birds and that the extracellular ubiquitination of ZP1 might occur during its transport via blood circulation.Reproduction 08/2012; 144(4):423-31. · 3.56 Impact Factor
Article: Zheng et al. reply.[Show abstract] [Hide abstract]
ABSTRACT: REPLYING TO G. Mayr & A. Manegold 499, http://dx.doi.org/10.1038/nature12367 (2013)Our explanation that structures preserved in three Early Cretaceous Jehol birds are ovarian follicles is challenged by Mayr & Manegold. We believe that their conclusions are speculative and do not take into account our original arguments. Contrary to Mayr & Manegold, unambiguous evidence for the preservation of less resistant tissue, such as muscles or internal organs, are not scarce among Jehol fossils (for example, fish, lampreys) and eggs are sometimes preserved in specimens of the sturgeon Peipiaosteus (J.-Y. Zhang, personal communication). Although we cannot explain the vagaries of taphonomy that lead to the preservation of ovarian follicles in these specimens, what is clear is that exceptional preservation of soft tissue is dictated by the unique chemical microenvironment created by the individual decaying tissues, and thus varied degrees of preservation within a single specimen is expected. Exceptional Jehol fossils are a reminder that simply because something is unlikely to preserve does not mean that it will not.Nature 07/2013; 499(7457):E1-E2. · 38.60 Impact Factor