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Relationship: 2685

Title

A descriptive phrase which clearly defines the two KEs being considered and the sequential relationship between them (i.e., which is upstream, and which is downstream). More help

Decrease, sox9 expression leads to Smaller and morphologically distorted facial cartilage structures

Upstream event
The causing Key Event (KE) in a Key Event Relationship (KER). More help
Decrease, sox9 expression
Downstream event
The responding Key Event (KE) in a Key Event Relationship (KER). More help
Smaller and morphologically distorted facial cartilage structures

Key Event Relationship Overview

The utility of AOPs for regulatory application is defined, to a large extent, by the confidence and precision with which they facilitate extrapolation of data measured at low levels of biological organisation to predicted outcomes at higher levels of organisation and the extent to which they can link biological effect measurements to their specific causes.Within the AOP framework, the predictive relationships that facilitate extrapolation are represented by the KERs. Consequently, the overall WoE for an AOP is a reflection in part, of the level of confidence in the underlying series of KERs it encompasses. Therefore, describing the KERs in an AOP involves assembling and organising the types of information and evidence that defines the scientific basis for inferring the probable change in, or state of, a downstream KE from the known or measured state of an upstream KE. More help

AOPs Referencing Relationship

AOP Name Adjacency Weight of Evidence Quantitative Understanding Point of Contact Author Status OECD Status
Aryl hydrocarbon receptor activation leading to early life stage mortality via sox9 repression induced impeded craniofacial development adjacent High Low Agnes Aggy (send email) Under development: Not open for comment. Do not cite EAGMST Under Review

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 KER.In general, this will be dictated by the more restrictive of the two KEs being linked together by the KER.  More help
Term Scientific Term Evidence Link
zebrafish Danio rerio High NCBI
rat Rattus norvegicus High NCBI
chicken Gallus gallus High NCBI
mouse Mus musculus High NCBI
Sebastiscus marmoratus Sebastiscus marmoratus High NCBI

Sex Applicability

An indication of the the relevant sex for this KER. More help
Sex Evidence
Unspecific High

Life Stage Applicability

An indication of the the relevant life stage(s) for this KER.  More help
Term Evidence
Embryo High
Development High

Key Event Relationship Description

Provides a concise overview of the information given below as well as addressing details that aren’t inherent in the description of the KEs themselves. More help
  • Sox9 is an important transcriptional regulator that has been implicated in several functions including craniofacial development, specifically via chondrogenesis or the formation of cartilage structure (Lefebvre and Dvir-Ginzberg 2017).
  • Additionally, exposure of different animals to relevant environmental pollutants leads to a significant decrease of sox9 expression (Garcia et al., 2017; Shi et al., 2017; Tussellino et al., 2016).
  • This KER provides lines of evidence linking the sox9 repression to alterations in craniofacial development and function.

Evidence Collection Strategy

Include a description of the approach for identification and assembly of the evidence base for the KER. For evidence identification, include, for example, a description of the sources and dates of information consulted including expert knowledge, databases searched and associated search terms/strings.  Include also a description of study screening criteria and methodology, study quality assessment considerations, the data extraction strategy and links to any repositories/databases of relevant references.Tabular summaries and links to relevant supporting documentation are encouraged, wherever possible. More help

Evidence Map 2.0

ID Experimental Design Species Upstream Observation Downstream Observation Citation (first author, year) Notes

Evidence Map

Addresses the scientific evidence supporting KERs in an AOP setting the stage for overall assessment of the AOP. More help
Title First Author
Biological Plausibility
Dose Concordance
Temporal Concordance
Incidence Concordance
Biological Plausibility
Dose Concordance Evidence
Temporal Concordance Evidence
Incidence Concordance Evidence
Uncertainties and Inconsistencies
Addresses inconsistencies or uncertainties in the relationship including the identification of experimental details that may explain apparent deviations from the expected patterns of concordance. More help
  • Few studies have showed an opposite relationship between sox9 expression and the size of cartilage structures.
    • Conditional knockout of setdb1 (histone methyltransferase) specifically in the murine Meckel’s cartilage led to and enlargement of the cartilage structure as well as the proliferation of chondrocytes, however, sox9 expression was significantly repressed (Yahiro et al., 2017).
    • Experimental unilateral anterior crossbite created in rats led to decreased ratio of the hypertrophic cartilage layer in the experiment group, which was evidence for obvious cartilage degradation. This was accompanied by induction of sox9 expression (Zhang et al., 2013b).
  • One recent zebrafish study using the CRISPR-Cas9 tool, demonstrated that sox9a but not sox9b was required for normal cartilage development (Lin et al., 2021). This is inconsistent with all previous research showing the importance of both sox9a and sox9b for cartilage development in zebrafish.

Known modulating factors

This table captures specific information on the MF, its properties, how it affects the KER and respective references.1.) What is the modulating factor? Name the factor for which solid evidence exists that it influences this KER. Examples: age, sex, genotype, diet 2.) Details of this modulating factor. Specify which features of this MF are relevant for this KER. Examples: a specific age range or a specific biological age (defined by...); a specific gene mutation or variant, a specific nutrient (deficit or surplus); a sex-specific homone; a certain threshold value (e.g. serum levels of a chemical above...) 3.) Description of how this modulating factor affects this KER. Describe the provable modification of the KER (also quantitatively, if known). Examples: increase or decrease of the magnitude of effect (by a factor of...); change of the time-course of the effect (onset delay by...); alteration of the probability of the effect; increase or decrease of the sensitivity of the downstream effect (by a factor of...) 4.) Provision of supporting scientific evidence for an effect of this MF on this KER. Give a list of references.  More help

Domain of Applicability

A free-text section of the KER description that the developers can use to explain their rationale for the taxonomic, life stage, or sex applicability structured terms. More help
  • Evidence suggests that sox9 and its function in craniofacial development (and thus its repression leading to craniofacial malformations), is an evolutionarily conserved phenomenon. This relationship appears to exist in almost all vertebrates and invertebrates that encode one or more versions of the sox9 gene.