"Molecular diversity of Dscam cell recognition proteins is essential for
neural circuit assembly"
Dr. Daisuke Hattori
Columbia University Medical Center&s_comma; Department of Neuroscience
The laboratory of Richard Axel&s_comma; U.S.A.
場所：東京大学 理学部2号館 第一講義室（２０１号室）
要旨：Precise wiring of neural circuits requires cellular recognition
mechanisms that mediate discrimination between neurites. The Drosophila Down
Syndrome Cell Adhesion Molecule (Dscam) gene encodes 19&s_comma;008 distinct cell
recognition proteins by virtue of extensive alternative splicing.
Biochemical and structural studies demonstrated that each isoform binds to
the same isoforms but not to different isoforms. Thus&s_comma; diversity of Dscam
isoforms provides thousands of recognition specificities. In this seminar&s_comma; I
will discuss a role of Dscam diversity and its vast recognition
specificities during neural circuit assembly. Molecular and genetic studies
indicated that Dscam diversity provides each neuron with a unique identity&s_comma;
thereby allowing each neurite to selectively recognize self-neurites
originating from the same neuron. This selective self-recognition underlies
a cellular phenomenon of neurite self-avoidance&s_comma; which supports efficient
elaboration of dendritic and axonal arbors over their receptive fields.
Recent studies demonstrated that thousands of Dscam isoforms are essential
to give rise to sufficiently large numbers of identities to faithfully
execute self-avoidance. Thus&s_comma; Dscam diversity provides a robust
discrimination mechanism underlying neurite self-avoidance during neural
Hattori D&s_comma; Chen Y&s_comma; Matthews BJ&s_comma; Salwinski L&s_comma; Sabatti C&s_comma; Grueber WB&s_comma; Zipursky
SL (2009) Robust discrimination between self and non-self neurites requires
thousands of Dscam1 isoforms. Nature 461&s_comma; 644-648.
Hattori D&s_comma; Millard SS&s_comma; Wojtowicz WM&s_comma; Zipursky SL (2008) Dscam-mediated cell
recognition regulates neural circuit formation. Annual Review of Cell and
Developmental Biology 24&s_comma; 597-620.
Hattori D*&s_comma; Demir E*&s_comma; Kim HW&s_comma; Viragh E&s_comma; Zipursky SL&s_comma; Dickson BJ (2007) Dscam
diversity is essential for neuronal wiring and self-recognition. Nature 449
問合せ先：東大・院理・生物科学 平良眞規 （03-5841-4434）
Tel/FAX: 03-5841-4434 (学内24434）
Masanori Taira&s_comma; Ph.D.
Department of Biological Sciences
Graduate School of Science
University of Tokyo