Defining Genomic Consequences of Chromothripsis Using a CRISPR-based Chromosome Labeling System

Background

Emerging evidence suggests that many cancers experience episodes of very rapid mutation. One example is a newly discovered mutagenic event called chromothripsis, in which one of the 46 DNA molecules (chromosomes) in the cell is heavily damaged, causing some segments of the chromosome to become scrambled, while others are lost altogether. Chromothripsis has been described in many cancers, but is particularly common in some pediatric cancers including sarcomas and gliomas.

The Pellman laboratory hypothesized that chromothripsis arises from cell division errors that cause one chromosome to be isolated in a structure called a micronucleus. Because micronuclei are small, abnormal versions of a normal nucleus, the lab proposed that micronuclei may act as mutation-generating factories that later pass along these mutations to cells' offspring. In order to test this prediction, they developed a method called "Look-seq" that allows them to determine how micronuclei observed under the microscope lead to mutations. Using this method, they showed that micronuclei can indeed generate a chromothriptic chromosome within a short period of time. 

Project Goal

However, in order to study how these mutations are driving tumor formation, we need to know the identity of the chromosome in the micronucleus from the outset, before it mutates. I will adapt a new genome editing tool called CRISPR to fluorescently mark a specific chromosome and achieve this goal.