In the Week 1 module, we are going to use an example gene of (mostly) unknown function from Arabidopsis, At3g20300, and see what online databases can tell us about that gene. Part A uses tools that we have explored in Plant Bioinformatics to gather information about the gene/gene product, such as its size, what its homologs are, phylogenetic relationship to other sequences, domain information, and subcellular localization. Part B explores gene expression databases to see where that gene is expressed. Often where and when a gene is expressed can give us clues as to its function.

Often the function of genes that are coexpressed with a gene of unknown function can give us hints about the function of that gene. Researchers are now often using coexpression analyses as “primary screens” to identify “new” genes in biological pathways (a few examples are described in Usadel et al., 2009). Another interesting facet is whether the promoters of these sets of coexpressed genes contain any common cis-regulatory motifs. In Part A, we’ll explore the genes that are coexpressed with At3g20300, and in Part B, we’ll look for common regulatory motifs.

Gene Ontology enrichment analysis for a set of coexpressed gene is often useful for figuring out what that group of genes is doing. By doing such analyses with a set of coexpressed genes can we infer a role for our gene of unknown function? We'll explore this aspect in Part A, along with investigating potential pathways the gene list is involved in. In Part B, we'll use other network tools to investigate additional linkages to other genes, above and beyond those suggested by coexpression. It is sometimes useful to investigate these too! Again, we'll be using At3g20300 as our example.

Now we will take the above analyses and synthesize the information from them into a draft lab report/essay describing the putative function of our gene of interest with unknown function. We'll draw on the literature to describe what is known about related genes, and propose some experiments to test our hypotheses about our gene's potential function.