# GO Tutorial: Annotating A Paper

## Exercise IV

### Annotation - Answers

Mutants with defects in RNA binding protein (RBP) are defective in cell growth and differentiation. An example RBP that regulates development is provided by the Bruno protein and its role as a translational repressor of oskar mRNA. In Drosophila, oskar is required for formation of germ cells and positioning of the posterior of the embryo.

Text string | GO Ontology | GO Term | GO ID
RNA binding | function | RNA binding | GO:0003723
cell growth | process | cell growth | GO:0016049
differentiation | process | cell differentiation | GO:0030154
translational repressor of oskar mRNA | process | negative regulation of oskar mRNA translation | GO:0007319
translational repressor of oskar mRNA | function | translation repressor activity | GO:0030371
formation of germ cells | process | germ-cell development | GO:0007281

Using microarray analysis, we identified RERG (ras-related and estrogen-regulated growth inhibitor). Like Ras, RERG protein exhibited intrinsic GDP/GTP binding and GTP hydrolysis activity. Unlike Ras proteins, RERG lacks a known recognition site for COOH-terminal prenylation and was localized primarily in the cytoplasm.

Text string | GO Ontology | GO Term | GO ID
estrogen-regulated | process | response to hormone stimulus | GO:0009725
growth inhibitor | process | negative regulation of cell growth | GO:0030308
Ras, GDP/GTP binding | process | small GTPase mediated signal transduction | GO:0007624
GDP/GTP binding | function | GDP binding | GO:0019003
GDP/GTP binding | function | GTP binding | GO:0005525
GTP hydrolysis | function | GTPase activity | GO:0003924
cytoplasm | component | cytoplasm |

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