***** seminarMLから情報転載 *****



日時: 平成19年12月17日(月曜日)10:30~12:00

会場: (財)東京都医学研究機構 東京都臨床医学総合研究所 2階 会議室
臨床研へは http://www.rinshoken.or.jp/intro/map.htm をご参考ください。

演題: Programming DNA replication origins on chromatin during cell
division and differentiation

演者: Marcel MECHALI博士&s_comma; Institute of Human Genetics&s_comma; CNRS&s_comma; 141
rue de la Cardonille&s_comma; 34396 Montpellier&s_comma; France.


In multicellular eukaryotes&s_comma; DNA replication origins are localized at
specific sites along the genome&s_comma; but they do not share a consensus
sequence. We suggested that a transition from strict
sequence-specific features to an epigenetic control linking DNA
replication origin selection with transcription contributes to
development. In a first part of this seminar&s_comma; I will report that DNA
replication origin selection is determined by the cell fate both in
Xenopus and in mouse. In Xenopus&s_comma; DNA replication origins are
developmentally regulated&s_comma; and correlate with the organization of
chromatin domains. Reprogramming of replicons and chromatin
organization also occurs during transfer of differentiated nuclei
into eggs. Mitosis is necessary for this reprogramming and involves a
topoisomeraseII-dependent process. We have also addressed the
regulation of DNA replication origins selection during neural
differentiation in the mouse HoxB domain&s_comma; a 120 Kbp cluster of nine
genes developmentally regulated. We observed a reorganization of the
HoxB domain for DNA replication when the HoxB domain is activated.
In a second part of this talk&s_comma; I will address how DNA
replication origins are assembled and controlled. The role of Cdt1&s_comma;
geminin&s_comma; and the recently discovered MCM9 protein will be particulary

Lutzmann et al&s_comma; (2006) EMBO J. 25&s_comma; 5764-5774.
Greoire&s_comma; et al&s_comma; (2006) EMBO Rep.&s_comma; 7&s_comma; 812-816.
Lemaitre&s_comma; et al&s_comma; (2005) Cell&s_comma; 123&s_comma; 787-801.
Maiorano et al (2005) Cell&s_comma; 120&s_comma; 315-28.
Danis et al&s_comma; (2004) Nature Cell Biol.&s_comma; 6&s_comma; 721-730.
Mehali&s_comma; M. (2001) Nat. Rev. Genetics&s_comma; 8&s_comma; 640-645.

電話 03-5685-2264

Hisao Masai
Genome Dynamics Project&s_comma;
Tokyo Metropolitan Institute of Medical Science&s_comma;
3-18-22 Honkomagome&s_comma; Bunkyo-ku&s_comma; Tokyo 113-8613&s_comma; JAPAN
Tel: 81-3-5685-2264; Fax: 81-3-5685-2932; E-mail: hmasai@rinshoken.or.jp