Toll (gene)

The Toll genes encode members of the Toll-like receptor class of proteins. ("Toll" is German for "amazing" or "mad".) [cite web |url=http://de.wiktionary.org/wiki/toll |title=toll - Wiktionary, das freie Wörterbuch – Das Wikiwörterbuch |accessdate=2007-11-10 |format= |work=] Toll genes were originally identified in the fruit fly "Drosophila melanogaster" in 1985, cite journal |author=Hansson GK, Edfeldt K |title=Toll to be paid at the gateway to the vessel wall |journal=Arterioscler. Thromb. Vasc. Biol. |volume=25 |issue=6 |pages=1085–7 |year=2005 |pmid=15923538 |doi=10.1161/01.ATV.0000168894.43759.47 |url=http://atvb.ahajournals.org/cgi/content/full/25/6/1085] , and cloned in 1988.cite journal |author=Hashimoto C, Hudson KL, Anderson KV |title=The Toll gene of Drosophila, required for dorsal-ventral embryonic polarity, appears to encode a transmembrane protein |journal=Cell |volume=52 |issue=2 |pages=269–79 |year=1988 |pmid=2449285 |doi=] Since then, eleven known mammalian Toll genes have been identified.

In flies, Toll was first identified as a gene important in embryogenesis in establishing the dorsal-ventral axis. In 1996, Toll was found to have a role in the fly's immunity to fungal infections. Both mammalian and invertebrate Toll genes are required for innate immunity.

Toll-like receptors in mammals were identified in 1997 at Yale University by Ruslan Medzhitov and Charles Janeway.cite journal |author=Medzhitov R, Preston-Hurlburt P, Janeway CA |title=A human homologue of the Drosophila Toll protein signals activation of adaptive immunity |journal=Nature |volume=388 |issue=6640 |pages=394–7 |year=1997 |pmid=9237759 |doi=10.1038/41131] . Concurrently, Bruce A. Beutler and colleagues discovered that the Toll-like receptors (TLRs) act as the principal sensors of infection in mammals . This latter discovery hinged on the positional cloning of the mammalian lipopolysaccharide (LPS) response locus, which identified the LPS receptor as TLR4 [ Alexander Poltorak, Xiaolong He, * Irina Smirnova, Mu-Ya Liu, dagger Christophe Van Huffel, ddagger Xin Du, Dale Birdwell, Erica Alejos, Maria Silva, Chris Galanos, Marina Freudenberg, Paola Ricciardi-Castagnoli, Betsy Layton, Bruce Beutler § Defective LPS Signaling in C3H/HeJ and C57BL/10ScCr Mice: Mutations in Tlr4 Gene http://www.sciencemag.org/cgi/content/abstract/282/5396/2085] .

Their name derives from Christiane Nüsslein-Volhard's 1985 exclamation, "Das war ja toll!"cite journal |author=Hansson GK, Edfeldt K |title=Toll to be paid at the gateway to the vessel wall |journal=Arterioscler. Thromb. Vasc. Biol. |volume=25 |issue=6 |pages=1085–7 |year=2005 |pmid=15923538 |doi=10.1161/01.ATV.0000168894.43759.47 |url=http://atvb.ahajournals.org/cgi/content/full/25/6/1085] The exclamation, which translates as "That's weird!" or "that´s cool/great", was in reference to the underdeveloped posterior portion of a fruit fly larva.

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