organisation - the Instituto Gulbenkian de Ciência

ORGANOGENESIS
Joaquín Rodríguez León Principal Investigator
PhD in Biology, University of Extremadura, Spain, 2000
Principal Investigator at the IGC since 2008
Our group focuses on the study of the cellular and molecular mechanisms controlling
limb development and fin regeneration. We are trying to understand
how the main signalling centre in limb development, the Apical Ectodermal
Ridge (AER), is established and maintained through development and how different
molecules, namely those related to stemness, are involved in these processes.
Also, we have developed a line of research directed to depict how ion
dynamics can control limb development, digit differentiation and fin regeneration.
In these studies we use the chicken and zebrafish embryos as well as adult
zebrafish as animal models.
ROLE OF STEMNESS GENES DURING FORMATION OF COMPLEX ORGANS
This project is framed into a general line of work in our lab that focuses on
the study of different genes that are involved in the maintenance of stemness
in vitro, and their in vivo role during development of complex organs. We are
studying how oct4 plays a role in the formation of limbs during vertebrate
development. Our main objective is to unveil how oct4 controls the activity of
a signalling centre essential for limb formation, the Apical Ectodermal Ridge
(AER). The aims of this project are:
GROUP MEMBERS
Ana Catarina Certal Afonso (Post-doc, left September)
Rui Castanhinha (PhD Student)
Joana Monteiro (External PhD student)
Rita Felix (Masters Student)
Ana Rita Aires (Research Technician)
COLLABORATORS
Yolanda Gañán Presmanes (University of Extremadura, Spain)
Domingo Macías Rodríguez (University of Extremadura, Spain)
Michael Levin (Tufts University, USA)
FUNDING
Fundação para a Ciência e a Tecnologia (FCT), Portugal
PUBLIC ENGAGEMENT IN SCIENCE
Talk for school students, Colegio Arias Montano, Badajoz, Spain (April)
Talk for school students, Escola Santo António e Escola António Aleixo,
Figueira de Castelo Rodrigo, Portugal (November)
1. To characterise oct4 expression during limb bud development;
2. To characterise the dynamics of proliferation versus apoptosis in the Apical
Ectodermal Ridge during limb bud development;
3. To understand the role of oct4 during limb bud development and its implication
in the maintenance of AER structure, function and cell behaviour;
4. To correlate the activity of FGFs, Wnts and RA and the control of oct4
expression with the AER structure, function and cell behaviour.
We have found that Wnts and Fgfs control and maintain oct4 expression in the proliferative
areas of the AER. On the contrary, BMPs and Retinoic Acid signaling act
as negative factors that abolish oct4 expression in the apoptotic areas of the AER.
We have also performed experiments involving pulses of BrdU and these manipulations
show that proliferative cells in the dorsal and ventral sides of the AER will
migrate towards its centre and will die by apoptosis. Manuscript is in preparation.
ION DYNAMICS DURING FIN REGENERATION
With this project we intend to assess the role of electric currents as coordinating
signals during the re-establishment of the P-D axis after amputation of
adult vertebrate appendages. We want to extend the current knowledge on the
molecular and cellular bases of bioelectric signals as well as the mechanisms
that convert them into cellular responses. The aims of this project are:
Limb bud after oct4 overexpression and double in situ for fgf8 (orange) and msx-1
(blue).
1. To describe the ion composition of electric currents associated with the regeneration
of caudal fins and to generate a spatial-temporal map of the intracellular
and extracellular dynamics of particular ion species during regeneration;
2. To unveil the molecular and cellular bases of ion dynamics associated with
regeneration;
3. To understand the role of specific ion transporters in the regeneration
mechanism;
4. To establish a link between ion dynamics and known molecular pathways
involved in the regeneration process.
We have demonstrated that during regeneration, a proton outward flux gradient is
established along the proximo-distal axis. Moreover, we have identified the V-AT-
Pase as the most likely molecular source that triggers the detected regenerationspecific
H+ efflux. Inhibition of this ion pump decreases regeneration rate. Hence,
we suggest that V-ATPase mediated proton flux in involved in the spatial coordination
of genes that will dictate the position-dependent rate of regeneration.
Scanning electron microscopy micrograph showing the surface of the regenerating
blastema in a zebrafish caudal fin 6 hours after amputation.
IGC ANNUAL REPORT ‘11
RESEARCH GROUPS
46