The Seventh Conference On Dna Topoisomerases In Therapy

October 21-24 (Monday-Thursday), 1996, Alumni Hall, New York University Medical Center, New York City

For more informations about the conference ->Click Here<-

Two posters were originally planned for the meeting: one authored by Agnès Beregerat et. all., and another one by D. Gadelle from our lab.
Only Agnès' poster has been actually displayed. We have left the second abstract for your convenience, as it appears in poster abstract summary.

#1 DNA topoisomerases of the hyperthermophilic archaeon Pyrococcus.furiosus 

#2 A DNA topoisomerase II of the archaeon Sulfolobus shibatae  (Topo VI) is the prototype of a new family, with eucaryal homologues possibly involved in meiosis


This is the abstract of the poster #1.

You may also have a look at an overview of the poster as it was setup during the congress.

Click on individual panes to view panels in full size. Here is text version for those who don't read maps.

DNA topoisomerases of the hyperthermophilic archaeon Pyrococcus furiosus 

Bergerat A.1, Bocs C.1,Borges K.M.2, DiRuggiero J.2, Robb F.T.2 and Forterre P.1
1 IGM, CNRS, Université Paris-Sud, France. 2The Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, MD.

Pyrococcus furiosus  is an hyperthermophilic archaeon which grows in anaerobic conditions with a temperature optimum of 98*C. Plasmid DNA of this organism is not negatively supercoiled but varies from relaxed to positively supercoiled state. To elucidate mechanisms that control supercoiling in this organism we have looked for all DNA topoisomerases activities present in this strain. Enzymatic activities as well as genes encoding DNA toposomerases suggest that P.furiosus exhibits a DNA topoisomerase I (from group A), a reverse gyrase and a type II DNA topoisomerase related to DNA topoisomerases VI a new type II DNA topoisomerase family. Enzymatic properties of these last two enzymes will be presented in details and correlated with DNA topology regulation.

General overview of the poster (graphical display)


Text version access to the poster panels:

Poster title
Elution profile of proteins
Relaxation of negative supercoiling and introduction of positive supercoiling
Type II topoisomerase of P. furiosus
Identification of the B subunit by fixation of an ATP analog
Comparison of the P. furiosus  enzyme with other archaeal type II DNA topoisomerases
The reverse gyrase of P. furiosus
P. furiosus  reverse gyrase gene
P. furiosus  reverse gyrase processivity
Comments on the type I topoisomerase of P. furiosus
Topodynamic in P. furiosus
Phylogenetic tree based on 16-18s rRNA sequences
Phylogenetic tree of Archae.


Abstract of the poster #2.

A DNA topoisomerase II of the archaeon Sulfolobus shibatae  (Topo VI) is the prototype of a new family, with eucaryal homologues possibly involved in meiosis

Gadelle D., Bergerat A., and Forterre P.
Institut de Génétique et Microbiologie, Université Paris-Sud, 91 405, Orsay, France

Type II DNA topoisomerases are found in the three domains of life : Bacteria, Eucarya and Archaea. All known type II DNA topoisomerases are homologues and form a single family. We have now cloned and sequenced the genes encoding for the two subunits of a type II DNA topoisomerase from the archaeon Sulfolobus shibatae . Surprisingly, this enzyme turned out to be the prototype of a new family. The B subunit, which binds ATP, only shares with others type II DNA topoisomerases three short motives involved in ATP binding and hydrolysis. We also found these motives in proteins of the Hsp90 and MutL families. The A subunit exhibits similarities with a putative protein of Caenorabditis elegans, and with two yeast proteins induced in early stage of meiosis. The hypothesis that these two yeast proteins could be responsible for double strand cleavage that initiate the meiotic recombination will be developped.

Last Revision on 11/15/96