Georgia Kafer

Our genetic information is encoded in DNA. DNA can be modified with small “tags” known as methylation (mC). In 2011 researchers found that there are different types of mC tags, one of which is hydroxymethylcytosine (hmC). For the last 5 years, researchers have been trying to figure out why DNA gets tagged with hmC. Some work has shown that hmC helps genes to be expressed and others have identified that a loss of hmC is associated with cancer. Our research showed for the first time that the hmC tag is associated with damaged DNA. We were able to use very high-resolution microscopy to show that hmC exists at damaged DNA sites in a variety of human and mouse cells. This discovery has far reaching implications for both cancer research and for research investigating how cells repair damaged DNA.

As with most research we made this discovery almost by “accident”. We were originally trying to develop a method to live-image hmC dynamics. To be confident in our live-imaging results we needed to know what the “normal” pattern of hmC was in the cell nucleus. When I looked at hmC using antibody-based methods in HeLa cells (a very common cancer cell line) I was very surprised to find that there were large “spots” of hmC. These hmC spots had never before been reported in the literature – but they reminded us very much of the sort of spots that some cells (particularly cancer cells) have which are associated with large regions of damaged DNA. We quickly ordered new antibodies that we could use to label damaged DNA and did dual staining to see if our hmC spots localized with the damage spots. They did. Perfectly. It was definitely a very exciting moment and I may have done a little “happy dance” in the dark microscope room before running to find my principle investigator!

Time was, like always, one of the biggest challenges. Research relating to hmC is very competitive as it is a relatively new “hot” area of chromatin biology. DNA damage was a research topic I only knew about superficially, so I had to spend a lot of time familiarizing myself with this new field. I had to learn on the fly – which included making some mistakes – to perform experiments common to DNA damage researchers but quite foreign to me. One particularly memorable challenge was creating a “home-made” system to induce laser-line damage to cell nuclei to test to see if hmC appeared at “new” damage sites. My principle investigator (Peter Carlton) and I spent many hours working in “production line” conditions trying to get a reproducible system to do this. We succeeded in the end and some of our beautiful “damage lines” made it into the manuscript.

I have always been quite fluid in my approach to research. I like to follow up on whatever interests me at any given time, so I have worked on topics ranging from glucose metabolism to in vitro embryo culture, mouse placental development, human stem cell differentiation and of course most recently DNA damage. However I do have to admit that I have been quite taken with DNA damage research. The DNA damage response of a cell is quite beautiful in how organized it is; yet fascinating in how complex the response may be via the incorporation of many redundant and compensatory mechanisms. Overall I definitely feel that my experience over the last 2 years has persuaded me to try and pursue DNA damage as a research focus. If I can mash this new research love with my old love of embryology and stem cell research then I will be a very happy scientist.

I completed my PhD almost 5 years ago in Australia, and I am currently a postdoctoral research associate in the Carlton Lab here at iCeMS. Our research is reasonably well funded (though more funding is always welcome!) and so I foresee myself working on this research topic for another year at least. Working at iCeMS has made my “research life” quite easy thanks to the wealth of resources available to me and access to programs designed to “accelerate research” – which was instrumental to the quick turnaround of our discovery into a publication. At iCeMS I have made several professional connections that I truly believe will last throughout my research career and which I will be able to draw upon in future projects. While I am very much enjoying my time in Japan, unless I get a very good offer here I think that one day I will return to work in my native country of Australia. I am sure that if this day comes then my affiliation with a well-regarded research-nexus such as iCeMS will assist me in my future career aspirations.

Carlton Lab

*All the information on this page, including the researcher’s affiliation, is current at the time of the interview.