Skip to content

GO Cellular Component

Before you make a GO annotation
  • Gene Ontology (GO) annotations are used to describe the normal (wild type) functions, processes and cellular components or locations of a gene product (protein or RNA).
  • Cellular components represent subcellular structures and macromolecular complexes, such as nucleus, nuclear inner membrane, nuclear pore, and proteasome complex.
  • Generally, a gene product is located in or is a subcomponent of a particular cellular component.
  • Gene products may be annotated with multiple cellular component terms.

Video summary

Making an annotation

On the Quick Links list, click on GO cellular component to open a window that requires you to indicate:

  • Gene: the gene that is located in a cellular component. See how to add genes.
  • Term name: a GO term describing the cellular component.
    • Start typing a cellular component in the search box. If you do not find the precise component you are looking for, choose a broad term (e.g. cytoskeleton, mitochondrion) that can be refined later.
    • Click the chosen term, and verify that the displayed definition describes the phenotype you want to annotate. There is sometimes a "Comment" section with extra tips for annotation.
    • If the blue button reads Next, click it and see if you can find a more specific term that the one you originally selected. If so, select it and do as before.
    • Otherwise, click Finish.
    • If you do not find the term you require, select a broader term, and request a new one clicking on Suggest a new term on the right side of the text box.
  • Annotation extension: this field appears once you have selected a GO term. Always click the Add button to see if you can specify:
    • Links to biological processes: observed in this location during can be used to indicate that gene product localizes to the cellular component during a cell cycle phase or cellular response to stimulus. For example, med7 localizes to euchromatin during "mitotic M phase".
    • Links to sequence ontology terms: found at genomic region indicates the type of DNA region for terms describing chromatin or chromosome regions. For example, man1 locates to the cellular component "heterochromatin" at "long terminal repeat" genomic regions.
    • Links to genes: similarly, found at genomic region can also specify the genes within the cellular component. For example, epe1 localizes to heterochromatin at the swi6 gene.
    • Modified form: sometimes, only a certain modified form of the gene product (e.g. phosphorylated) localizes in the cellular component. This is very valuable information, but requires a PR ontology term to exist for the modified version of the protein, which is rare. You can include this information in the comment section (e.g. write: "phosphorylated form").
  • Evidence code: the type of experiment where the phenotype was observed.
  • Comment: it's very useful for us if you indicate the figure or table where this phenotype comes from.