Using Chemical Genetics to Define the Precise Role of RUNX1 in Transcription and Beyond
Germline mutations in RUNX1 causes affected individuals to have problems with bleeding and proper blood clotting. These patients also have an increased chance of developing a form of blood cancer during their lifetime, but what predicts whether cancer will form or not is unknown. This means we also don’t know how to stop the development of blood cancer in these patients. The mutations in RUNX1 cause the loss of RUNX1 activity. To understand how the loss of RUNX1 activity causes disease, we need to first understand what RUNX1 normally does to keep the cells involved in blood clotting functioning normally. We know that RUNX1 is a transcription factor, which means that is a protein that regulates how other genes in the cell are read. However, it had been difficult to define the genes regulated by RUNX1, because we didn't have any way to rapidly turn the RUNX1 protein on or off. We have now generated a model that will allow us to rapidly remove the RUNX1 protein from cells to not only define the genes regulated by RUNX1, but also to determine how RUNX1 regulates the way genes are read, and to determine how this affects the development and function of cells responsible for clotting.
Project Goal: The goal of this project is to determine what genes RUNX1 controls, how it controls them, and how mutations associated with RUNX1-FPDMM change the way RUNX1 works. We hope that if we understand what RUNX1 normally does, we’ll be able to understand how things go wrong when it is mutated, and how we might be able to fix it to keep patients from developing cancer. In the past, it has been hard to study what RUNX1 normally does, because old technology took a long time (days to weeks) to get rid of RUNX1. Lots of things can change in days to weeks, and not all of them are directly related to RUNX1. We now have a way to get rid of RUNX1 in 2 hours, which will allow us to define the direct functions of RUNX1 and finally learn exactly how RUNX1 works. Understanding how RUNX1 works will be key to identifying new targeted therapies to prevent RUNX1-FPDMM patients from developing blood cancers.
Project Update 2024:
Some mutations in the RUNX1 gene can be passed from parent to child. These mutations either prevent the RUNX1 protein from being made or cause it to not function properly. We are trying to understand what the RUNX1 protein does normally in the cell, so that we can better understand the consequences of RUNX1 mutations. We think of RUNX1 as a protein that regulates when and how other genes are turned on. RUNX1 turns genes on and off very quickly, therefore in order to catch these rapid gene changes, we have developed a way to quickly modulate the levels of RUNX1 protein. Thus, we are determining which genes that RUNX1 regulates and how it does this. Interestingly, we have found that RUNX1 regulates many of the same genes as other transcription factors that are mutated in people with platelet dysfunction including FLI1 and GATA1. In addition, we know that patients with RUNX1 mutations have elevated levels of DNA damage, which could cause the accumulation of more gene mutations. We are using our fast system of RUNX1 depletion to also uncover the mechanisms that underly these elevated levels of DNA damage in patient cells. We have observed higher levels of RUNX1 protein after DNA damage and are trying to figure out what the cause and consequence of increased RUNX1 is for the DNA damage response.
