This help document answers the following questions:
The Gene Expression Database (GXD) is designed to integrate many different types of endogenous gene expression data from the mouse in formats appropriate for comprehensive analysis. Query results, such as the developmental stage and tissue of expression (or non-expression), the genetic origin of the sample, and the numbers and sizes of detected bands, are described together with the molecular probe, the expression assay type, and the experimental conditions used. Expression patterns are described using an extensive, hierarchical dictionary of standardized anatomical terms, making it possible to record expression results from assays with differing spatial resolution in a consistent and integrated manner and to analyze expression patterns at differing levels of detail. Whenever possible, text annotations are complemented by digitized images of the original expression data.
To learn more about GXD and how we acquire data, please see About GXD.
See also the MGI Glossary for unfamiliar terms and acronyms.
The Gene Expression Data Query form Standard Search tab allows you to ask questions that can be basic or complex. Examples of the type of questions you can ask are:
(See Are there examples of query results? for the form field values for these queries.)
If you are interested in doing queries that ask what genes are expressed in some anatomical structures and/or developmental stages but not in others, you should use the Differential Expression Search tab on this form.
To search for detailed data using this query form, enter or select values in one or more of the query form fields described in the following table. After entering values in the query form fields, click Search to submit the query. Click Reset to clear the fields and return any default values.Top
|Genes | Anatomical structure or stage | Mutant / wild type | Assay types|
|Genes||This section offers a choice of two fields.
Nomenclature search. Use the left hand field to search for expression data for a mouse gene or set of genes with a similar nomenclature.
Vocabulary term search. Use the right hand field to find expression data for genes defined by their function, phenotype or disease model association.
Note that you may not submit a search with values in the Nomenclature search and the Vocabulary Term search at the same time.
|Anatomical structure or stage||
Click to limit your search to assay results where expression was detected in, not detected in, or either. The default value is either.
You can choose to use one or both fields in this section.Anatomical Structures
The anatomical structures are taken from the Anatomical Dictionary. Begin typing an anatomy term of interest and an autocomplete list activates on the second character. The list shows all the anatomy terms and their synonyms that match your search characters. You must choose a term from the autocomplete list (i.e., there is no free text entry in this field).
For each developmental stage, the Anatomical Dictionary is organized as a hierarchy of structures. By default, the search includes substructures. This means if you search for gene expression in, for example, brain, this searches for all terms that contain the word brain and the substructures to those terms in the hierarchy, such as rhombencephalon.
If you are unsure of the most appropriate structural term to use, browse the Anatomical Dictionary.Developmental Stages (dpc)
Use this field to select one or more Theiler stages (TS) to focus your search on a particular stage of embryonic development. Alternately, you can choose the Use Ages tab and limit your search to the general terms, Embryonic or Postnatal, or choose days post conception (dpc).
Note: The Theiler system organizes development into stages defined by the appearance of specific developmental features. Embryos of the same gestational age can vary considerably with respect to development. Consequently, a Theiler stage does not precisely correspond to a particular age. For example, TS 21 applies to embryos between 12.5 and 14.0 days post conception (dpc), while TS 22 applies to embryos between 13.5 and 15.0 dpc.To select multiple stages or ages:
If you mouse-over a stage, a pop-up will describe a few defining features of that stage, such as "first somites, late head fold" for Stage 12. You can browse Stage descriptions for a list of the defining features for each Theiler stage. Please note that in GXD all annotations of postnatal animals use Theiler Stage 28.
|Mutant / wild type||
Select Specimens mutated in gene to search for expression data obtained from mutant specimens. Use this field to enter the symbol or name of the mutated genetic marker. The system searches for current symbols/names and synonyms of the mutated gene. Use this search field as you would the Genes' nomenclature search at the top of the search form.
Select Wild type specimens only if you wish to exclude mutant alleles from your search. This search will still include knock-in reporter genes used in in situ reporter assays. Homozygous mutant specimens are not included in this search.
Select All specimens, the default, to include all mutant and wild type specimens in your search.
|Assay types||Check list of assay types. Use this section to limit your search to assays of one or more selected types. The default is to search All of the assay types on the list. Uncheck the first box for Find expression data in any assay type to quickly clear all selections.|
The Differential Expression Search is specifically designed to allow you to search for genes expressed in some anatomical structures or developmental stages but not in others. Examples of the questions you can ask are:
Yes, you can.
Your search results are displayed within four tabs, each noting the number of results: Genes, Assays, Assay Results and Images. With the Standard search, the Assay Results tab is selected by default. For Differential Expression searches, the Genes tab is the default selection.
If you select the Genes tab, the query summary contains the following fields:
MGI ID MGI accession ID for the Gene Gene Symbol of the analyzed gene, linked to its MGI marker detail record Gene Name Name of the analyzed gene Type Marker feature type for the analyzed gene. See Genome Feature Type Definitions. Chr Chromosome to which the marker is assigned. Aside from a chromosome number, other possible values include MT (mitochondrial), XY (XY pseudoautosomal), UN (chromosome assignment is not known) Genome Location-NCBI Build # Genome coordinate range in base pairs and the build number of the B57BL/6J genome cM Cytogenetic position Strand Coding strand for the gene
If you select the Assays tab, the query summary contains the following fields:
Gene Symbol of the analyzed gene. Assay Details The word data links to detailed expression results; the MGI accession ID of the assay (useful for searching purposes) appears in parentheses. A camera icon appears when there are image data associated with the assay. Assay Type Name of the assay used (e.g., Immunohistochemistry, Northern blot, RNA in situ, and so on). Reference J number (MGI identifier) and short format citation for this reference linked to its MGI reference detail report.
If you select Assay Results, the query summary contains the following fields:
Gene Symbol of the analyzed gene Result Details The word data links to detailed expression results; the MGI accession ID of the assay (useful for searching purposes) appears next in parentheses Assay Type Name of the assay used (e.g., immunohistochemistry, Northern blot, RNA in situ) Anatomical System High-level term for the anatomical system assayed (e.g. Cardiovascular System, Extraembryonic Component) Age Age of the specimen used in the assay. Whenever possible, the age annotations are normalized according to the following conventions: noon of the day on which the vaginal plug is found is counted as embryonic (E) day 0.5. Therefore, e.g., if an author refers to the day on which the plug is found as E0, we add 0.5 to the age value(s) listed in the paper and the comment Age normalized so that noon of plug day = E0.5 to the record. If the staging criteria are not described in the paper, we annotate to the ages given by the authors and may add the comment Age of embryo at noon of plug day not specified in reference to the record. The abbreviations for age annotations are as follows:
E Embryonic day P Postnatal or postnatal day P w Postnatal week P m Postnatal month P y Postnatal year P adult Postnatal adult P newborn Postnatal newborn Structure Structure examined in the assay, given as a Theiler stage (TS) and anatomical structure name Detected? Was expression detected? Possible values include:
- Not specified
Note: Not specified is used when the authors do not report whether a gel band is present or absent. Ambiguous is used when the curators cannot discern from the author's description whether expression is present or absent.
Images Name of the specimen or pane with associated images, linked to the appropriate section of the assay detail. Note: Images are shown only when we have permission from the publishers. Mutant Allele(s) If the specimen is a mutant, the allele pairs describing the mutant genotype appear in this field. Reference J number (MGI identifier) and short format citation for this reference linked to its MGI reference detail report
If you select the Images tab, the query summary contains the following fields:
Figure A thumbnail image, linked to the MGI Image Detail page. Gene Symbol of the analyzed gene(s). Assay Type Name of the assay(s) used (e.g., Immunohistochemistry, Northern blot, RNA in situ, and so on). Result Details Links to image and expression assay result details.
At the end of the query summary, there may be a link to Gene Expression Literature content records matching the parameters of your detailed expression data search.
Thus, to ensure that your query returns all the references of interest to you, searches of the detailed expression data also include searches of the literature content records (whenever query parameters apply to both these types of data).
The following detailed expression data query parameters generate an expression literature search:
Because of the limited annotation of content records, the following parameters do not generate an expression literature search:
Note: You can query gene expression literature content records directly using the Gene Expression Literature Query Form.Top
Yes. The Genes and Assay Results tabs but not the Assays tab, provide export options. In your search results, click on the Text File or Excel File icon. Your web browser will download a file of the results.Top
Yes. Under the Genes tab you have the option of exporting your results as a text file, spreadsheet file or sending the list of genes to the MGI Batch Query. If you click the Batch Query icon, the default Batch Summary will appear for your list of genes. Use the Click to modify search button to expand your search results to include additional information such as Gene Ontology (GO) terms, Mammalian Phenotype (MP) terms or Human Diseases associated with the genes.
See also Using the MGI Batch Query.Top
The following examples list the field values to set on the Gene Expression Data Query Form to perform each query. Leave the default values in all other fields.
Genes…Search for expression data for…: en1
This query returns a list of results from assays examining En1 expression. This summary report includes the gene symbol, result details linked to an assay record (click data), the assay type used, the anatomical system assayed, the age of the specimen, the specific structure examined, an indication of whether or not expression was detected, links to images, the mutant allele pairs describing the mutant genotype of the specimen (if applicable), and the reference from which the data were curated, linked to its abstract.
Expression: detected in
Anatomical Structures: heart
Developmental Stages (dpc): Select the Ages (dpc) tab and then E8.5
Mutant / wild type: Wild type specimens only
This query returns a list of assay results for genes expressed in the heart at E8.5. Click the Genes tab to view a summary report that includes the gene symbols (with links to MGI detail pages), gene types and genomic map coordinates. The report does not include any expression results obtained from mutant alleles. Note: Each developmental stage in the example includes coverage of embryonic day 8.5. See Theiler System for details.
Genes…Search for expression data for…:wnt*
Expression: detected in
Developmental Stages (dpc): TS 16
This query returns a list of assay results for Wnt family genes whose expression was detected in Theiler Stage 16.
Genes…A set of genes defined by: axon guidance
This query returns a list of all assay results for all genes known to be involved in mouse axon guidance.
Expression: not detected in
Anatomical Structure(s): diencephalon
This query returns a list of genes found not to be expressed in the diencephalon or in anatomical structures within the diencephalon, such as the hypothalamus, 3rd ventricle, or pituitary gland.
Genes...A set of genes defined by: cell adhesion
Expression: detected in
Anatomical Structures: stomach mesenchyme
This query returns a list of genes involved in cell adhesion found to be expressed in the stomach mesenchyme.
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Tumor Biology (MTB), Gene Ontology (GO), MouseCyc
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