François Jacob

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François Jacob

ForMemRS
Born(1920-06-17)17 June 1920[2]
Nancy, France
Died19 April 2013(2013-04-19) (aged 92)[2]
Paris, France
Alma materUniversity of Paris
Known forOperon model[3][4]
Spouses
  • Lise Bloch (4 children)
Geneviève Barrier
​
(m. 1999)​
Awards
Scientific career
FieldsMolecular biology

François Jacob (17 June 1920 – 19 April 2013) was a French

André Lwoff.[2][5][6][1]

Early years

Jacob was born the only child of Simon, a merchant, and Thérèse (Franck) Jacob, in

atheist.[7]

Though interested (and talented) in physics and mathematics, Jacob was horrified at the prospect of spending two additional years in "an even more draconian regime" to prepare for higher study at the

Polytechnique. Instead, after observing a surgical operation that cemented his "slight interest" in medicine, he entered medical school.[8]

During the German occupation of France—and on the heels of his mother's death—Jacob left France for Great Britain to join the war effort. Jacob, who had only completed his second year of medical studies, joined the medical company of the

croix de guerre
.

After his recovery, Jacob returned to medical school and began researching tyrothricin[10] and learning the methods of bacteriology in the process. He completed a thesis he described as "replicating American work" on the effectiveness of the antibiotic against local infections, and became a medical doctor in 1947. Though attracted to research as a career, he was discouraged by his own perceived ignorance after attending a microbiology congress that summer. Instead, he took a position at the Cabanel Center, where he had done his thesis research; his new work entailed the manufacture of an antibiotic, tyrothricin. Later, the center was contracted to convert gunpowder factories for penicillin production (though this proved impossible).[11]

Also in this period, he met and began courting his future wife, Lise Bloch.[12] Jacob remarried in 1999 to Geneviève Barrier.[13]

Research

In 1961 Jacob and Monod explored the idea that the control of

transcription of DNA sequences. Their experiments and ideas gave impetus to the emerging field of molecular developmental biology, and of transcriptional regulation
in particular.

For many years it had been known that bacterial and other cells could respond to external conditions by regulating levels of their key

metabolic enzymes, and/or the activity of these enzymes. For instance, if a bacterium finds itself in a broth containing lactose, rather than the simpler sugar glucose, it must adapt itself to the need to 1) import lactose, 2) cleave lactose to its constituents glucose and galactose, and 3) convert the galactose to glucose. It was known that cells ramp up their production of the enzymes that do these steps when exposed to lactose, rather than wastefully producing these enzymes all the time. Studies of enzyme activity control were progressing through theories of the (allosteric) action of small molecules
on the enzyme molecule itself (switching it on or off), but the method of controlling the enzyme production was not well understood at the time.

With the earlier determination of the structure and central importance of DNA, it became clear that all proteins were being produced in some way from its genetic code, and that this step might form a key control point. Jacob and Monod made key experimental and theoretical discoveries that demonstrated that in the case of the lactose system outlined above (in the bacterium E. coli), there are specific proteins that are devoted to repressing the transcription of the DNA to its product (RNA, which in turn is decoded into protein).

This repressor (the

feedback loop
is constructed that allows the set of lactose-digesting proteins products to be made only when they are needed.

Jacob and Monod extended this repressor model to all genes in all organisms in their initial exuberance. The regulation of gene activity has developed into a very large sub-discipline of molecular biology, and in truth exhibits enormous variety in mechanism and many levels of complexity. Current researchers find regulatory events at every conceivable level of the processes that express genetic information. In the relatively simple genome of baker's yeast, (Saccharomyces cerevisiae), 405 of its 6,419 protein-encoding genes are directly involved in transcriptional control, compared to 1,938 that are enzymes.

Honours and awards

See also

References

  1. ^
    ISSN 0080-4606
    .
  2. ^
    PMID 23698437
    .
  3. PMID 14406329. Archived from the original
    (PDF) on 4 March 2016. Retrieved 27 August 2015.
  4. S2CID 5051714
    .
  5. ^
    S2CID 30313937
    .
  6. ^ "Nobel-winning biologist Francois Jacob dies at 92". The Raw Story. Archived from the original on 9 September 2014. Retrieved 22 April 2013.
  7. ^ Jacob, The Statue Within, pp 20–57. Quotes from pp 42 and 53.
  8. ^ Jacob, The Statue Within, pp 84–88. Quote from p 86
  9. ^ Jacob, The Statue Within, pp 98–165
  10. ^ Jacob, "The Statue Within", pp 194–95
  11. ^ Jacob, The Statue Within, pp 166–199
  12. ^ Jacob, The Statue Within, pp 199–206
  13. ISBN 978-9810234126
    .
  14. ^ "Francois Jacob". American Academy of Arts & Sciences. Retrieved 13 September 2022.
  15. ^ "Francois Jacob". www.nasonline.org. Retrieved 13 September 2022.
  16. ^ "APS Member History". search.amphilsoc.org. Retrieved 13 September 2022.

Bibliography

External links

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