BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Three phases of Wnt signaling define three phases of axis developm
 ent in the hemichordate S. kowalevskii - Jens Fritzenwanker (Stanford Univ
 ersity)
DTSTART:20160127T130000Z
DTEND:20160127T140000Z
UID:TALK62636@talks.cam.ac.uk
CONTACT:Marcia Kishida
DESCRIPTION:The Wnt signaling pathway is a key regulator of body plan orga
 nization and axis formation in all metazoans. We have analyzed the develop
 mental role of Wnt signaling in the hemichordate _Saccoglossus kowalevskii
 _ to gain insights into deuterostome and bilaterian body plan evolution. O
 ur data suggest that _S. kowalevskii_ is the only known bilaterian retaini
 ng the full Wnt complement of the bilaterian ancestor - a characteristic t
 hat indicates a slow evolving genome.\nWe have analyzed the roles of Wnt s
 ignaling in endomesoderm formation (Darras et al. 2011)\, axial patterning
 \, and posterior axis elongation. We show that in contrast to chordates wh
 ere these processes are thought to be linked\, in _S. kowalevskii_ these a
 re independent and discreet processes during development. We further show 
 that unlike in chordates where an anterior-posterior Wnt-gradient is being
  read out for axis specification and patterning\, in _S. kowalevskii_ the 
 AP-axis is first divided into three large domains (anterior\, center\, and
  posterior) from which surprisingly only the anterior and center domain ar
 e specified by Wnt signaling. First after domains are specified is the AP-
 axis patterned by Wnt signaling\, including the posterior.\nBy examining W
 nt\, Notch signaling and _brachyury_ we further show that posterior axis e
 longation is not a continuation of initial posterior patterning and gastru
 lation as proposed for chordates but rather is an independent developmenta
 l program identifiable by the rewiring of the posterior network around the
  time of gastrulation. We discuss the comparative implications of this wor
 k for understanding the early evolution of bilaterian axial patterning.
LOCATION:Part II Lecture Theatre\, Department of Zoology
END:VEVENT
END:VCALENDAR