Women in Biology

An introduction to Elizabeth Blackburn and Jennifer Doudna

Introduction to Elizabeth Blackburn

Elizabeth Blackburn is responsible for the groundbreaking discovery of telomeres. Derived from the Greek telos (end) and meros (part), these are structures made from DNA sequences and proteins and act as buffers at the ends of chromosomes, which are the DNA molecules containing the genetic material of an organism.

Blackburn also discovered telomerase, an enzyme which contributes to the longevity of cells. These two pioneering discoveries earned Blackburn the Nobel Prize in Physiology or Medicine in 2009 “for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase”[1].

She has received nearly every major award in science, including the Gairdner Foundation International Award (1998), the Albert Lasker Award for Basic Medical Research (2006), and United States National Academy of Sciences Award in Molecular Biology (1990). 

She has held numerous prestigious positions, including President of the American Association for Cancer Research in 2010 and President of the Salk Institute for Biological Studies (2016-17). The Salk Institute is a non-profit scientific research institute that explores “the very foundations of life, seeking new understandings in neuroscience, genetics, immunology, plant biology and more.”[2]

Blackburn’s Early Life & Education

Blackburn was born in 1948, in Tasmania, Australia, to physician parents. The 2nd of 7 children, she grew up in the city of Hobart and, over the years, the family had many different kinds of pets, which Blackburn was very fond of. Her fascination with animals contributed to her interest in biology, and, by the time she was in her late teens, she was confident she wanted to pursue a career in science[3].

Blackburn attended the Broadland House Girls Grammar School, but, as physics wasn’t offered at the school, she took evening physics classes at the local public high school. She graduated from University High School in Melbourne.

She earned her BSc (1970) and MSc (1972), both in biochemistry, from the University of Melbourne. In 1975, Blackburn obtained her PhD from Cambridge University for her work on bacteriophage viruses, which are a specific type of virus that infects bacteria.

Blackburn’s Discovery of Telomeres

In 1978, Blackburn took up a teaching position at University of California at Berkeley, and, in 1990, she moved to University of California at San Francisco (UCSF) in the Department of Microbiology and Immunology where she served as Chair from 1993 to 1999.

At UCSF, Blackburn made the groundbreaking discovery of telomeres in chromosomes and the telomerase enzyme. Chromosomes carry genetic information in the form of genes, and, as cells in the body divide, chromosomes replicate so that each cell contains a complete set of chromosomes. 

Blackburn discovered that at the end of each chromosome there are stretches of DNA called telomeres which act as buffers, protecting the end of the chromosome from damage or fusing with nearby chromosomes. Each time a chromosome replicates, the telomeres prevent genes from being lost in the process.

Blackburn’s Discovery of Telomerase

Following her discovery of telomeres and the fundamental role they play in preserving chromosomes, Blackburn, along with PhD student Carol W. Greider, also discovered the telomerase enzyme. 

During chromosome replication, telomeres shorten. Blackburn and Greider realized that the telomerase enzyme prevents too much wear and tear of the telomeres by adding additional telomere sequences to the end of chromosomes, hence contributing to the longevity of the cell. 

Telomeres and telomerase play central roles in aging and diseases such as cancer, and Blackburn’s work launched entire new fields of research in these areas. For example, shorter telomeres have been found to increase the risk of certain cancers such as bladder and lung cancers[4], though no one is sure why. 

In a 2016 study, telomerase was found to be increased in more than 90% of cancers, which implies that cancer[5] cells have the ability to use telomerase to protect their telomeres and, as a result, delay their deterioration. As a result, certain new cancer treatments are being developed to target telomerase in order to destroy cancer cells faster[6].

Blackburn on the President’s Council of Bioethics

In 2002, Blackburn was appointed to the President’s Council of Bioethics by then President George W. Bush. Her support of use of human embryonic stem cells in biomedical research did not accord with the White House and, in 2004, she was removed from Council amid heated public controversy. 

The Union of Concerned Scientists published an article soon after Blackburn’s removal going as far as to say that it was a violation of the Federal Advisory Committee Act of 1972: “This action violated the spirit, if not the letter, of the Federal Advisory Committee Act of 1972, which requires balance on such advisory bodies.”[7]

On the controversy, Blackburn wrote: “There is a growing sense that scientific research—which, after all, is defined by the quest for truth—is being manipulated for political ends.”[8]

Introduction to Jennifer Doudna

Jennifer Doudna is a pioneer in genome editing and is known for her discovery of a molecular tool known as Clustered Regularly Interspaced Short Palindromic Repeats or CRISPR. Her revolutionary discovery has allowed researchers to make specific changes to DNA and modify the genome of living organisms.

Doudna has received numerous awards and distinctions, culminating in the Nobel Prize in Chemistry, which she received in 2020 together with Emmanuelle Charpentier “for the development of a method for genome editing.”[9]

Other honors include the Breakthrough Prize in Life Sciences (2015) and the Wolf Prize in Medicine (2020). Doudna is a member of the National Academy of Sciences, the National Academy of Medicine, the National Academy of Inventors, and the American Academy of Arts and Sciences. 

She is currently a Professor of Chemistry, Biochemistry & Molecular Biology at University of California, Berkeley and is the founder of 5 different companies that use CRISPR across diagnostics, human therapeutics, and sustainability.

Doudna’s Early Life & Education

Doudna was born in 1964, in Washington, D.C., and spent much of her childhood in Hilo, Hawaii, due to her father’s teaching position in American Literature at the University of Hawaii at Hilo. Growing up in Hawaii with its lush nature, greatly influenced Doudna’s fascination with the biological mechanisms of life and her hunger for scientific discovery[10].

When Doudna was in 6th grade, her father gave her a copy of James Watson’s book The Double Helix, which focused on the discovery of the DNA structure, and which significantly influenced her future career path. Once in high school, mathematics and chemistry further enhanced her innate scientific curiosity. She spent a summer working at the lab of University of Hawaii at Hilo under the supervision of Don Hemmes, a prominent mycologist, in other words, a biologist who studies fungi.

Following her graduation from Hilo High School in 1981, Doudna received her BA in biochemistry from Pomona College in California in 1985 and then went on to Harvard Medical School, where she earned her PhD in Biological Chemistry & Molecular Pharmacology in 1989.

Doudna’s Early Career & Research

Early in her career, Doudna held research fellowships in molecular biology at Massachusetts General Hospital and in genetics at Harvard Medical School, followed by conducting postdoctoral research at the University of Colorado Boulder.

While in Colorado, Doudna studied RNA enzymes called ribozymes in an effort to determine their 3-dimensional structure and provide an insight into RNA’s catalytic activity. According to Britannica, RNA, or ribonucleic acid, is a “complex compound … that functions in cellular protein synthesis and replaces DNA as a carrier of genetic codes in some viruses.” 

In 1994, Doudna became an assistant professor at Yale’s Department of Molecular Biophysics and Biochemistry and in 2000 was promoted to full professor, while also serving as a visiting Professor of Chemistry at Harvard in 2000/01.

Doudna as a Professor

In 2002, Doudna moved to University of California, Berkeley, as a professor of biochemistry and molecular biology. Doudna has said that she decided to move to Berkeley because of its “interesting pioneering spirit”[11] but also because of its proximity to the U.S. Department of Energy’s Lawrence Berkeley National Laboratory. This is where high-intensity X-ray beams are produced and assist in probing the complex structure of proteins and other molecules.

It was at Berkeley that Doudna made the groundbreaking discovery of CRISPR, and where she currently serves as Li Ka Shing Chancellor’s Chair a Professor in the Departments of Chemistry and of Molecular and Cell Biology.[12]

Doudna and CRISPR-Cas9

In 2012, Doudna and French microbiologist Emmanuelle Charpentier discovered a molecular tool known as Clustered Regularly Interspaced Short Palindromic Repeats or CRISPR-Cas9. CRISPR-Cas9 has provided the foundation for gene editing which allows scientists to make specific alterations to DNA sequences unlike ever before. This is possible with the use of an enzyme that acts as a pair of molecular scissors to cut 2 strands of DNA on a specific area so that removal or addition of DNA can be performed.[13]

Research into genome editing therapies is already underway, focusing primarily on ‘monogenic’ diseases, such as cystic fibrosis, which are caused by a single defective gene and thus the simplest to correct by rewriting. Furthermore, scientists are exploring the use of CRISPR-Cas9 to target bacterial genes that present resistance to antibiotics, which could lead to a breakthrough against antibiotic-resistant bacteria. 

The possibilities that have arisen from Doudna’s groundbreaking discovery could be limitless. As she has said: “We’ve been able to read and write DNA for a long time…What we haven’t been able to do is to rewrite it—to edit it. And now we have a tool that lets you do something about that… That is incredibly exciting.”[14]

Doudna Safeguarding the Human Genome

Despite her groundbreaking discovery, Doudna has become a leading voice of caution for the appropriate use of the technology, urging scientists to be conscious of the ethics surrounding CRISPR and all that it enables. While the ability to cure genetic and hereditary diseases can be hailed as progress, using genetic engineering technology to modify non-disease traits, such as intelligence and beauty, raises both safety and ethical concerns.

In 2015, Doudna led an effort that called for a moratorium on human genome editing using CRISPR. Together with a group of other leading biologists, she set out the framework for safeguarding human embryos from modification in a way that can be inherited – also called germline gene editing.

George Q. Daley, a stem cell expert at Boston Children’s Hospital and a member of the group[15], said at the time: “It raises the most fundamental of issues about how we are going to view our humanity in the future…[and] take control of our genetic destiny, which raises enormous peril for humanity.”[16]

Doudna’s Other Projects

Besides her teaching positions and research at Berkeley, Doudna is also involved in several other initiatives and research projects. In 2017, she cofounded Mammoth Industries, a bioengineering tech startup and CRISPR disease-detecting company based in San Francisco. Its aim is to “discover novel CRISPR methods that enable new possibilities for expanding biology”[17] to address challenges across healthcare, agriculture, environmental monitoring, and biodefense.

Doudna has cofounded and is as advisory member on several panels that use CRISPR technology in a unique way. Furthermore, she is the founder and President of the Innovative Genomics Institute, which uses genome engineering to “solve humanity’s greatest problems in health, climate, and sustainable agriculture”[18] while guiding the ethical use of the technology. 

Doudna has been an investigator with the Howard Hughes Medical Institute since 1997. In addition, she is a director at Johnson & Johnson, while also heading pivotal research projects with, among others, Biogen, Pfizer, and Roche.

Sources

[1] The Nobel Prize. Elizabeth H. Blackburn. Facts. https://www.nobelprize.org/prizes/medicine/2009/blackburn/facts/

[2] The Salk Institute. About Salk. https://www.salk.edu/about/ 

[3] The Nobel Prize. Elizabeth Blackburn. Biographical. https://www.nobelprize.org/prizes/medicine/2009/blackburn/biographical/

[4] National Library of Medicine. Roles of telomeres and telomerase in cancer, and advances in telomerase-targeted therapies. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4915101/

[5] As above.

[6] Healthline. Telomeres: The Key to Staying Young and Disease-Free? https://www.healthline.com/health/telomeres

[7] Union of Concerned Scientists. President’s Council on Bioethics. April 11, 2004. https://www.ucsusa.org/resources/attacks-on-science/presidents-council-bioethics

[8] The New England Journal of Medicine. Perspective. Bioethics and the Political Distortion of Biomedical Science. Elizabeth Blackburn, PhD. April 1, 2004. https://www.nejm.org/doi/full/10.1056/NEJMp048072

[9] The Nobel Prize. Jennifer A. Doudna. https://www.nobelprize.org/prizes/chemistry/2020/doudna/facts/

[10] Cal Alumni Association. Cracking the Code: Jennifer Doudna and Her Amazing Molecular Scissors. https://alumni.berkeley.edu/california-magazine/winter-2014-gender-assumptions/cracking-code-jennifer-doudna-and-her-amazing

[11] Cal Alumni Association. Cracking the Code: Jennifer Doudna and Her Amazing Molecular Scissors. https://alumni.berkeley.edu/california-magazine/winter-2014-gender-assumptions/cracking-code-jennifer-doudna-and-her-amazing

[12] Doudna Lab. https://doudnalab.org/bio/

[13] Cas9. What is CRISPR-Cas9 and How Does it Work? https://cas9.com/what-is-crispr-cas9-and-how-does-it-work/

[14] Cal Alumni Association. Cracking the Code: Jennifer Doudna and Her Amazing Molecular Scissors. https://alumni.berkeley.edu/california-magazine/winter-2014-gender-assumptions/cracking-code-jennifer-doudna-and-her-amazing

[15] The New York Times. Scientists Seek Ban on Method of Editing the Human Genome. https://www.nytimes.com/2015/03/20/science/biologists-call-for-halt-to-gene-editing-technique-in-humans.html?_r=0

[16] Genomics.Ca. Scientists Seek Ban on Method of Editing the Human Genome. Nicholas Wade. https://genomics.ca/scientists-seek-ban-on-method-of-editing-the-human-genome/

[17] Mammoth Industries. https://mammoth.bio

[18] Innovative Genomics Institute. https://innovativegenomics.org

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