Mark Ptashne is a molecular biologist and violinist. He holds the Ludwig Chair of Molecular Biology at Memorial Sloan–Kettering Cancer Center in New York. His lifelong work has been the elucidation of the molecular mechanisms of switch between lytic and lysogenic lifecyle of bacteriophage lambda and

 how yeast transcriptional activator Gal4 works.He asked questions via e-mails while writing his little book Genes and Signals.

In his laboratory, they study basic mechanisms of gene regulation, primarily in yeast at the moment, but with an eye to understanding many basic aspects of biological regulation. One recently published books, based on their earlier work, describes the protein-protein and protein-DNA interactions that underlie a complex gene regulatory circuit in phage lambda (A Genetic Switch 3rd ed., Ptashne, 2004); and another (Genes and Signals, Ptashne and Gann 2002), shows how these underlying mechanisms are at work in eukaryotes as well. Moreover, the latter book shows how the principle mechanism of transcriptional regulation --"recruitment" -- is also used to regulate the activity of a wide array of enzymes including polymerases, kinases, phosphatases, ubiquitylases, proteases, and so on. The picture that emerges describes how evolution can use the same enzymes to produce a fly and a human. They are now immersed in a study of how gene regulators deal with the fact that genes in eukaryotes are wrapped in nucleosomes, using new techniques for quantitating nucleosome formation. A short recent essay (Ptashne 2007) shows how thinking about this problem sheds light on current ideas about 'epigenetics.'

Honors
Albert Lasker Medical Research Award (1997)
Gairdner Foundation International Award (1985)
Louisa Gross Horwitz Prize (1985)
    
Publications
Ptashne M. Transcription: a mechanism for short-term memory. Curr Biol. 2008 Jan 8;18(1):R25-7.
Ptashne M. Repressors Curr Biol. 2007E Sep 4;17(17):R740-1.
Ptashne M. Word. Curr Biol. 2007D Jul 17;17(14):R533-5.
Ptashne M. On learning to write. Curr Biol. 2007C Jun 5;17(11):R394-5.
Ptashne M. On speaking, writing and inspiration. Curr Biol. 2007B May 15;17(10):R348-9.
Ptashne, M. Essay: "On the Use of the Word 'Epigenetic'". Current Biology 2007A Vol 17 No 7, R233-236.
Ptashne, M (2004). A Genetic Switch: Phage Lambda Revisited (3rd ed.). Cold Harbor Spring Laboratory Press. ISBN 978-087969716-7. 
Ptashne, M; Gann, A (2002). Genes and Signals. Cold Harbor Spring Laboratory Press. ISBN 978-087969633-7.