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Event: 307

Key Event Title

A descriptive phrase which defines a discrete biological change that can be measured. More help

Increase, Vitellogenin synthesis in liver

Short name

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Biological Context

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE. More help

Level of Biological Organization
Tissue

Organ term

The location/biological environment in which the event takes place.The biological context describes the location/biological environment in which the event takes place. For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable. For individual/population events, the organ context is not applicable. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Organ term
liver

Key Event Components

The KE, as defined by a set structured ontology terms consisting of a biological process, object, and action with each term originating from one of 14 biological ontologies (Ives, et al., 2017; https://aopwiki.org/info_pages/2/info_linked_pages/7#List). Biological process describes dynamics of the underlying biological system (e.g., receptor signalling).Biological process describes dynamics of the underlying biological system (e.g., receptor signaling). The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signaling by that receptor). Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description. To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons. If a desired term does not exist, a new term request may be made via Term Requests. Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Process	Object	Action
gene expression	vitellogenins	increased

Key Event Overview

AOPs Including This Key Event

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE.Clicking on the name of the AOP will bring you to the individual page for that AOP. More help

AOP Name	Role of event in AOP	Point of Contact	Author Status
Estrogen receptor agonism leading to reproductive dysfunction	KeyEvent	Undefined (send email)	Under Development: Contributions and Comments Welcome
ER agonism leads to reduced survival/population growth	KeyEvent	Camille Baettig (send email)	Under development: Not open for comment. Do not cite
ER agonism leads to reduced fecundity	KeyEvent	Jason M. O'Brien (send email)	Under development: Not open for comment. Do not cite

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KE.In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE. More help

Life Stages

An indication of the the relevant life stage(s) for this KE. More help

Sex Applicability

An indication of the the relevant sex for this KE. More help

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided. More help

Vitellogenin (VTG) is an egg yolk precursor protein synthesized by hepatocytes of oviparous vertebrates (Hara et al., 2016). Transcription of vtg is regulated by estrogens and their interaction on ERs. In males expression can be modulated by exogenous compounds. Under high estrogen stimulation the fold increase of vtg transcripts increases by orders of magnitude (Brock & Shapiro, 1983).

How It Is Measured or Detected

A description of the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements.These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA). Do not provide detailed protocols. More help

Relative abundance of vitellogenin transcripts or protein can be measured in liver tissue (e.g., Miracle et al., 2006), hepatocytes (e.g., Vaillant et al., 1988), exposed in vitro, or whole-body homogenates from organisms exposed in vivo (Holbech et al., 2001).

mRNA transcripts can be measured using real-time quantitative polymerase chain reaction (qPCR) while protein quantification can be measured using alkali-labile phosphoprotein (e.g., Kramer et al., 1998), or immunochemical methods such as radioimmunoassay (RIA; e.g., Tyler & Sumpter, 1990), enzyme linked immunosorbent assay (ELISA; e.g., Denslow et al., 1999), and Western blotting (e.g., Heppell et al., 1995).

Domain of Applicability

A description of the scientific basis for the indicated domains of applicability and the WoE calls (if provided). More help

Taxonomic applicability: Oviparous vertebrates.

Although vitellogenin is conserved among oviparous vertebrates and many invertebrates, liver is not a relevant tissue for the production of vitellogenin in invertebrates (Wahli, 1988).

Life stage: This KE is applicable to all life stages following the differentiation of the liver. Embryos prior to liver differentiation should not be included.

Sex: This KE is applicable to both sexes.

References

List of the literature that was cited for this KE description. More help

Brock, M. L., & Shapiro, D. (1983). Estrogen regulates the absolute rate of transcription of the Xenopus laevis vitellogenin genes. Journal of Biological Chemistry, 258(9), 5449-5455.
Denslow, N. D., Chow, M. C., Kroll, K. J., & Green, L. (1999). Vitellogenin as a biomarker of exposure for estrogen or estrogen mimics. Ecotoxicology, 8, 385-398.
Hara, A., Hiramatsu, N., & Fujita, T. (2016). Vitellogenesis and choriogenesis in fishes. Fisheries Science, 82(2), 187-202. https://doi.org/10.1007/s12562-015-0957-5
Heppell, S. A., Denslow, N. D., Folmar, L. C., & Sullivan, C. V. (1995). Universal assay of vitellogenin as a biomarker for environmental estrogens. Environmental Health Perspectives, 103(suppl 7), 9-15.
Holbech, H., Andersen, L., Petersen, G. I., Korsgaard, B., Pedersen, K. L., & Bjerregaard, P. (2001). Development of an ELISA for vitellogenin in whole body homogenate of zebrafish (Danio rerio). Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 130(1), 119-131.
Kramer, V., Miles-Richardson, S., Pierens, S., & Giesy, J. (1998). Reproductive impairment and induction of alkaline-labile phosphate, a biomarker of estrogen exposure, in fathead minnows (Pimephales promelas) exposed to waterborne 17β-estradiol. Aquatic Toxicology, 40(4), 335-360.
Miracle, A., Ankley, G., & Lattier, D. (2006). Expression of two vitellogenin genes (vg1 and vg3) in fathead minnow (Pimephales promelas) liver in response to exposure to steroidal estrogens and androgens. Ecotoxicology and environmental safety, 63(3), 337-342.
Tyler, C. R., & Sumpter, J. P. (1990). The development of a radioimmunoassay for carp, Cyprinus carpio, vitellogenin. Fish Physiology and Biochemistry, 8, 129-140.
Vaillant, C., Le Guellec, C., Pakdel, F., & Valotaire, Y. (1988). Vitellogenin gene expression in primary culture of male rainbow trout hepatocytes. General and Comparative Endocrinology, 70(2), 284-290.
Wahli, W. (1988). Evolution and expression of vitellogenin genes. Trends in Genetics, 4(8), 227-232.