I currently work with Dr. Joshua Dubnau on researching how Tar-Binding-Protein-43(TDP-43) aggregation leads to retrotransposon element activation and neurodegeneration. Retrotransposable elements (RTEs) are mobile genetic elements that comprise about 35% of the human genome and are referred to as “junk” DNA because they are never expressed¹. In neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Frontal Temporal Lobe Dementia (FTLD), and Alzheimer’s Disease (AD), there is an association between TAR-Binding Protein-43(TDP-43) aggregation and RTE activation, leading to DNA damage and apoptosis, as depicted in figure one. In normal cells, TDP-43 is shown to silence RTE expression. However, its aggregate form leads to RTE expression and neurodegeneration.

To visualize the replication of retrotransposons, reporter constructs were created based on a reporter system known as CLEVR, as shown in figure two. The CLEVR reporter construct was designed to specify the replication and expression of the RTE mgd4². It also consists of a dual reporter module that can highlight cell morphology. Currently, I am testing the functionality of these new reporter constructs using drosophila experiencing TDP-43 pathology. After dissecting and staining the drosophila glial cells, the experimental results would show if TDP-43 is a causal pathway in RTE activation.

Applications of this study can identify causal pathways by visualizing those pathways through reporter constructs. Using the tools developed in this research, novel diagnostics can be developed to assess stages of neurodegeneration. A future research focus of mine would be creating reporter constructs that allow calcium signaling to be measured and quantified along with visualizing retrotransposon activation.

Figure One: Effects of TDP-43 Pathology on RTE Activation and Cell Death¹

Figure Two: CLEVR Reporter Constructs ²

Citations:

1 Gorbunova, V. et al. The role of retrotransposable elements in ageing and age-associated diseases. Nature 596, 43-53, doi:10.1038/s41586-021-03542-y (2021).

2. Chang, Y. H., Keegan, R. M., Prazak, L. & Dubnau, J. Cellular labeling of endogenous retrovirus replication (CLEVR) reveals de novo insertions of the gypsy retrotransposable element in cell culture and both neurons and glial cells of aging fruit flies. PLoS Biol 17, e3000278, doi:10.1371/journal.pbio.3000278 (2019).