Figure 1.

Example of a target model and data figure taken from the BRCA Tumors in-class problem set. Images were taken from a published research article (Bryant et al., 2005; Helleday et al., 2005); the explanatory box pointing to collapsed replication fork was added. Figure legends were written by the course instructor and were provided to students. The target model shows PARP protein repairing single-stranded breaks (SSB) in DNA, but if inhibited, the SSB can cause a collapsed replication fork, which includes a double-stranded break in DNA that BRCA2 protein repairs through homologous recombination. Therefore cancer cells that are BRCA2-deficient are sensitive to PARP inhibition. The data figure consists of two line graphs that show how cancer cells missing BRCA2 are more sensitive to PARP inhibitor drugs than wild-type cancer cells containing BRCA2; and this phenotype can be rescued to behave similar to wild type by complementing BRCA2.