Professor Jennifer Doudna

Born 19th February, 1964 (Washington DC, United States)

Doudna first made her name uncovering the basic structure and function of the first ribozyme, a type of catalytic ribonucleic acid (RNA) that helps catalyse chemical reactions. This work helped lay the foundation for her later helping to pioneer CRISPR-Cas 9, a tool that has provided the means to edit genes on an unprecedented scale and at minimal cost. In addition to her scientific contributions to CRISPR, Doudna is known for spearheading the public debate to consider the ethical implications of using CRISPR-Cas9 to edit human embryos.

Jennifer Doudna (Photo credit: Royal Society)

Family

Jennifer Anne Doudna was born in Washington DC. When she was seven years old she moved with her parents to Hilo, a small non-touristy town on the largest island of Hawaii, where her father became a professor in English literature at the University of Hawaii and her mother taught history at a local community college. Landing up in a place where most of the children were of Polynesian and Asian descent and came from a blue-collar background, Doudna always felt slightly out of place with her fair hair, blue eyes and academic parents. She often retreated into books or exploring the rugged volcanic landscape, beaches and lush vegetation of the island.(Kahn, Pollack)

Growing up surrounded by the natural beauty and ecological diversity of Hawaii, Doudna quickly acquired an appreciation for nature and became fascinated with science. Both of Doudna’s parents, who had a passion for astronomy, geology and evolution, encouraged her interest in science, supplying her with books on various topics and taking her to museums.(Marino) One summer they arranged for her to some spend time with Don Hermes, a biologist and family friend at the University of Hawaii. He set her the task with two other students to investigate how one particular fungus, Phytophthora palmivora, infected papyrus. While the project only last a few weeks, they managed to determine that calcium ions played an important role in the development of the fungus. During her time with Hermes, Doudna also learnt how to embed fungus in resin and shave off sections for examining under an electron microscope. Doudna retains many fond memories of that summer. As she says, 'It was my [first] taste of the thrill of scientific discovery, an experience that I’d read so much about - and it left me hungering for more.'(Doudna and Sternberg)

Doudna first became interested in biochemistry when she was about 12 or 13. This was inspired by two particular events. The first one was reading James Watson personal account of his discovery of the double helix of DNA in his book, which her father left on her bed one rainy afternoon. The second was when she heard a lecture by a young female scientist about how normal cells became cancerous. This she heard while attending a summer programme at Honolulu cancer center. Both events ignited Doudna’s desire to pursue a career that would allow her to explore the mysteries of life.(Doudna and Sternberg; Kahn)

Doudna shares her interest biochemistry with her husband, Jamie Cate. The two of them first met in the early 1990s at the University of Colorado where he was a graduate student and she a postgraduate researcher. In 2002 Doudna gave birth to their son, Andrew. Doudna see her son as her ‘biggest experiment’. (Marino).

Education

In 1985 Doudna completed a bachelor's degree in chemistry at Pomona College in Claremont, California. She chose the college because it was small and on the west coast. It also had a strong biochemistry programme. A number of chemistry professors made a profound impression on her during her undergraduate years. One of these was Sharon Panasenko in whose laboratory she conducted her first scientific research. Panasenko struck Doudna not only because of her scientific talent, but also because she demonstrated how to be a successful woman in the male-dominated world of science.(Marino)

After Pomona College Doudna went to Harvard University where, in 1989, she finished a biochemistry doctorate under the supervision Jack Szostak, a geneticist who would go on to win a Nobel Prize in 2009 for helping to determine how telomeres and the enzyme telomerase protect the chromosome. Her doctoral research focused on ribonucleic acid (RNA). This is a nucleic acid that is a cousin of DNA. It is present in all cells and involved in the synthesis of proteins. Doudna focused her research specifically on ribozymes. These are a type of catalytic RNAs that help catalyse chemical reactions of proteins. Entering the field of RNA at that time was hugely exhilarating for Doudna as scientists were only just then beginning to appreciate how much of a role the molecule played inside cells.

Career

Doudna’s doctorate proved to be just the beginning of a long career trying to work out the chemistry underlying RNA’s many biological functions. Like many around her, she was intrigued by the idea that RNA could provide some clues about the origins of life.

Following her doctorate, Doudna spent some time working with Szostak and then left to take up a postgraduate fellowship in the laboratory of Thomas Cech at the University of Colorado in Boulder. One of the attractions of going to work with Cech was that he had just won the Nobel Prize, in 1989, for discovering the catalytic properties of RNA.(Marino) He also had the equipment to carry out X-ray diffraction which would help her decipher the three-dimensional atomic structure of RNA. With no formal training in x-ray diffraction, Doudna spent many of her early days in Cech’s laboratory acquiring the skill alongside crystallising RNA molecules in preparation for imaging them.

In 1994 Doudna left Cech’s laboratory to take up a position as an assistant professor at Yale University. Six years later she was promoted to become the Henry Ford II Professor of Molecular Biophysics and Biochemistry. In 2002, Doudna moved to the University of California, Berkeley, where she was appointed Professor of Biochemistry and Molecular Biology. Berkeley was particularly appealing to Doudna because it allowed her to be closer to her mother in Hawaii and her extended family. It also gave her access to the facilities of the Lawrence Berkeley National Laboratory. She was particularly keen to use the Laboratory’s synchroton, a huge machine that provides high intensity X-ray beams. This would provide her with the means her to delve deeper into the complex structure of proteins and other molecules. (Russell)

Achievements

One of Doudna’s first breakthroughs occurred when she was still a doctoral student in Szostak’s laboratory. She helped demonstrate that RNA not merely carries instructions from DNA for synthesising proteins but also helps catalyse the process. (Doudna, Szostak) Published in 1989, their work helped revolutionise RNA research. Seven years later Doudna announced, together with Cech, the three-dimensional structure of the P4-P6 domain of the Tetrahymena thermophila group I intron ribozyme, a particular type of RNA. It was a major achievement because prior to this only one other single RNA structure had been unravelled, transfer RNA (tRNA), and it was much smaller and simpler than the ribozyme. Working with Cech and others, including Cate - her future husband, Doudna helped demonstrate that the ribozyme had a defined shape and an organised structure similar to proteins.(Cate et al; Marino) By 1998, Doudna and her team had determined the crystal structure of their first viral RNA - the hepatitis delta virus (HDV), a human pathogen linked to hepatitis B. By working on the structure of HDV they hoped to determine how viral RNAs functioned so as to develop treatments to combat viral disease. (Marino)

Doudna is now closely linked to the invention of a new tool for gene editing that has radically reduced the time and work needed to edit the genome. Originally this began as just a side-project from her main research. As narrated in her book with Sternberg (2017), it all started in 2005 with a phone call from Jillian Banfield, a colleague at Berkeley, who wanted Doudna to help her understand some repetitive sequences she had spotted in the genomes of some bacterial communities she was studying from highly acidic wastewater from a mine in northern California. Banfield was curious to know whether the sequences, known as CRISPR (clustered regularly interspaced short palindromic repeats), could be some form of RNA mechanism the bacteria used to protect themselves from viral infection. Never having come across CRISPR before, Doudna quickly got swept up in trying to figure out how CRISPR worked. Such work she believed could provide some clues into how small RNA molecules in human cells regulated genes and the pathways of RNA interference, a topic that she and her group were then investigating. She was also intrigued by the notion that bacteria might have a human-style immune system that recorded previous diseases to curb a future attack. Up to this moment scientists had assumed bacteria only had a rudimentary immune system.(Kahn, Mukhopadyay; Witowski)

A few years later, in March 2011, Doudna went to an American Society for Microbiology conference in Puerto Rico where she met Emmanuelle Charpentier, a French microbiologist and geneticist then based at Umea University in Sweden. Charpentier had noticed a mysterious enzyme, Cas9, associated with CRISPR that appeared to help Streptococcus pyogenes, a type of flesh-eating bacteria that causes many important human diseases, fend off invading viruses. Immediately warming to Charpentier, Doudna agreed to partner with her to find out more and sent over Martin Jinek, her postdoctoral researcher from the Czech Republic, to work with her. Thereafter a number of other researchers came on board, including Michael Hauser, a master’s student from Germany who worked in Doudna Laboratory, and Krystztof Chylinski a Polish doctorate student of Charpentier who was based in her old laboratory at the University of Vienna.(Doudna and Sternberg)

After many months the collaborators figured out that the CRISPR defense mechanism consisted of two separate RNA molecules (CRISPR RNA and tracRNA) which helped guide Cas9 to snip out a piece of DNA at a precise point on the genome. Bacteria used the mechanism as a means to slice up viral DNA whenever and wherever it invaded a cell. Soon after they had puzzled this out, it suddenly dawned on Doudna and Jinek that the same bacterial defense system could be re-engineered in the laboratory to provide a tool for editing genes in all kinds of cells from different organisms. Within a short time they had demonstrated in test tubes using a jellyfish gene, called green fluorescent protein, that this was possible. What surprised them was how straightforward and easy the system was to use. Indeed, it was much less laborious and much faster than previous methods for gene editing, such as Zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs). In 2012 the whole team published their findings in Science, concluding ‘our methodology based on RNA-programmed Cas9 …. could offer considerable potential for gene targeting and genome editing applications.’(Jinek) The paper quickly grabbed the attention of molecular biologists and geneticists who grasped the method’s significance. Following this, both Doudna and other scientists proved the technique could be used in human cells.

Since 2012 Doudna has been swept up in the whirlwind of excitement that CRISPR-Cas9 has fueled for many different applications. CRISPR-Cas-9 has the key advantage that it is easy to engineer. It is also very inexpensive. For example, it is 150 times cheaper than ZFNs. In addition, it is more precise. (Wang) Just how revolutionary the technique is proving can be seen from the case of engineering genetically modified mice, an animal model widely used to study genetics and the pathways of disease. Prior to the arrival of CRISPR-Cas9 engineering a mouse with a single mutation could take nearly two years. Now this can be achieved in just one month. (Cohen, Doudna & Sternberg)

While a great achievement, CRISPR-Cas9 poses many ethical questions for Doudna. Her main concern is the use of the technology in human embryos before it has been adequately shown to be safe. She has been at the forefront of public debates on this issue and was behind the 2015 effort to get a temporary worldwide moratorium on the clinical use of the technique in human embryos before its safety had been proven and its consequences fully considered. Since then she has begun to rethink her position after hearing some of the heart-breaking stories of children suffering from genetic disorders. (Devlin)

Doudna has won numerous awards in her time and on 7th October 2020 she was jointly awarded Nobel Prize for Chemistry together with Emanuelle Charpentier for their development of gene editing. When asked about her success, Doudna comments that much of it was down to her luck in having good mentors early on in her career and having had the freedom to build up her laboratory team with people with whom she shares a personal chemistry and the same scientific vision and drive. A key essence for her is to have laboratory with a supportive environment where people work together as a team and older members are prepared to mentor those who are younger. Much of her achievement she also attributes to Kaihong Zhou, her laboratory manager, who has worked with her for over thirty years, starting from when Doudna was at Yale University. The two of them confer on everything all the way from what projects to run through to what staff to hire and how to allocate funds. (Mukhopadyay)

This profile was originally written by Lara Marks, Oct 2017.

References

Cate, J. H., Gooding, A. Podell, E., Zhou, K., Golden, B., Kundrot, C., Cech, T. R., & J.A. Doudna, Science, 273 (1996), 1678–1685.

Cohen, J., 'Any idiot can do it.' Genome editor CRISPR could put mutant mice in everyone's reach', Science Magazine, 3 Nov 2016.

Doudna, J.A. and Sternberg, S., A Crack in Creation (London, 2017).
Doudna, J. A., Cormack B.P. and Szostak, J. W., Science, 244 (1989), 692–694.

Jinek, M., Chylinski, K., Fonfara, I., Hauer, M., Doudna, J. A., Charpentier E., et al, ‘A Programmable Dual-RNA–Guided DNA Endonuclease in Adaptive Bacterial Immunity’, Science, 337/6097 (2012), 816-21.

Kahn, J., ‘The Crispr Quandary’, The New York Times, Nov 9 2015.

Marion, M., ‘Biography of Jennifer A Doudna’, PNAS , 101/49 (2004),16987–16989, doi:10.1073/pnas.0408147101.

Mukopadyay, R., ‘On the same wave length’, ASBMB Today, Aug 2014.

Pollack, A. ‘Jennifer Doudna, a Pioneer Who Helped Simplify Genome Editing’, Science, May 11 2015.

Russell, S., ‘Cracking the Code: Jennifer Doudna and Her Amazing Molecular Scissors’, California Magazine, Winter 2014.

Wang, B., ‘Disruptive CRISPR gene therapy is 150 times cheaper than zinc fingers and CRISPR is faster and more precise’, Next Big Future, June 9 2015.

Witowski, J., ‘A conversation with Jennifer Doudna’, Cold Spring Harb Symp Quant Biol, 80 (2015), 314-315.

Jennifer Doudna: timeline of key events