2 Department of Morphological Sciences and Cell Biology, University of

Extremadura, School of Biology, Badajoz, Spain

The prospective dorsal prosencephalon includes rostrally the

telencephalic domain, which later evaginates bilaterally after neu-

rulation, producing the telencephalic vesicles, and caudally the

diencephalic domain. Fate maps of the chick and zebrafish neural

plates have so far mapped the telencephalic field, showing that

the prospective subpallium lies rostrally, whereas the pallium lies

caudally, adjacent to the rostral diencephalon. The origin of the

chick telencephalic domain and its regionalization into subpallial

and pallial areas are not well understood at gastrula stages. In

order to examine these aspects, we performed a detailed fate

map of the prospective telencephalic domain by using homotopic

fluorescent grafts, combining these data subsequently with an ISH

map of molecular changes in expression patterns detected at

three stages:HH4 (gastrula stage; fate according to present data),

HH8 (open neural tube; fate according to Cobos et al., 2001) and

HH10/11 (closed neural tube; fate according to Pombero and Mar-

tinez, 2009). The prospective telencephalon occupies after gastru-

lation a dorsal domain across the roof and dorsal alar plate of the

secondary forebrain, which is continuous from left to right across

the prospective preoptic area. The dorsalmost domain of the ros-

tral forebrain corresponds to the anterior neural ridge (ANR)where

an incipient molecular partition of the telencephalic domain is

molecularly defined by Fgf8,Ganf,Lhx9 and Pax6 at stages HH7/8-

9.Early on, the rostrocaudal telencephalic domains – pallium and

subpallium – are completely segregated and differential molecular

identities start to appear likewise at stage HH8. Work supported by

the Spanish Ministry of Science and Innovation Grants BFU2005-

09378-C02-01 and BFU2008-04156 to L.P,and BFU2006-15330-C02-

02 to LRG.L.S.A. is a predoctoral FPI fellow. L.P, J.L.F. and L.S.A.

are researchers of the CIBER en Enfermedades Raras, U736 (Minis-

try of Science and Technology, Spain).

doi:10.1016/j.mod.2009.06.148

03-P096

In vivo analyzes of dystroglycan function during somitogenesis

in Xenopus laevis

Magdalena Hidalgo1,2, Cathy Sirour1, Valerie Bello1,

Nicole Moreau1, Michele Beaudry2, Thierry Darribere1

1 Universite Pierre et Marie Curie – UMR CNRS 7622 – Biologie du

Developpement, Paris, France2 Universite Paris 13 – EA 2363 – UFR-SMBH, Bobigny, France

Dystroglycan (Dg) is a cell adhesion receptor for laminin that

has been reported to play a role in skeletal muscle cell stability,

cytoskeletal organization, cell polarity, and signaling. Here we

show that Dg is expressed at both the notochord/somite and

the intersomitic boundaries, where laminin and fibronectin are

accumulated during somitogenesis. Inhibition of Dg function

with morpholino antisense oligonucleotides or a dominant nega-

tive mutant results in the normal segmentation of the presomitic

mesoderm but affects the number, the size, and the integrity of

somites. Depletion of Dg disrupts proliferation and alignment of

myoblasts without affecting XMyoD and XMRF4 expression. It

also leads to defects in laminin deposition at the intersomitic

junctions, whereas expression of integrin 1 subunits and fibro-

nectin assembly occur normally. Our results show that Dg is crit-

ical for both proliferation and elongation of somitic cells and that

the Dg-cytoplasmic domain is required for the laminin assembly

at the intersomitic boundaries.

doi:10.1016/j.mod.2009.06.149

03-P097

Is the process of epithelio-mesenchymal transformation involved

in the dental lamina regression?

Marcela Buchtova1,2, Jan Stembırek1, Eva Matalova1,2,

Ivan Mısek1,2

1 Institute of Animal Physiology and Genetics, v.v.i., Brno, Czech

Republic2 University of Veterinary and Pharmaceutical Sciences, Brno, Czech

Republic

The epithelio-mesenchymal transformation (EMT) is a process

when epithelial cells change the cellular phenotype, lose the cell–

cell adhesion along with their mobility encouragement. At early

stages of craniofacial development, cranial neural crest (CNC)

cells undergo EMT and migrate away from the dorsal neural tube

to accommodate craniofacial prominences. Later, the EMT occurs

in the horizontal palatal shelves during the palate fusion.

In the prenatal period, there are continuous morphological

changes happening within the dental lamina of minipig embryos.

Cells facing tooth anlagen start to contain acidophil cytoplasm

with enlarged cytoplasmic processes and some of them are dis-

connected from the lamina. While apoptosis was not confirmed

as the main mechanism of lamina regression, we aim to test

the possibility of epithelio-mesenchymal transformation of lam-

ina cells. Here, we examine the presence of EMT markers MMP2

and E-cadherin at protein level by immunohistochemical detec-

tion. E-cadherin plays important roles in cell adhesion and we

found the differences of E-cadherin expression on the oral and

aboral parts of dental lamina. At later stages of lamina regression,

the presence of E-cadherin was decreased on both sides of the

lamina. MMP2 is a degenerative enzyme involved in the basement

membrane breakdown. The elevation of MMP2 occurred on the

aboral side of dental lamina where acidophilic cells are present.

The dynamic pattern of both EMT markers during the regression

of dental lamina was in the agreement with the changes appear-

ing in CNC cells or palate seam.

The research is supported by GACR (304/08/P289) and IRP IPAG

No. AVOZ 5045015.

doi:10.1016/j.mod.2009.06.150

03-P098

Integrating the genetics, mechanics and phenomenology of

embryonic wound healing

Marco Antunes1, Shane Hutson2, Wayne Brodland3,

Antonio Jacinto1

S95M E C H A N I S M S O F D E V E L O P M E N T 1 2 6 ( 2 0 0 9 ) S 6 7 – S 1 0 6