Chair: Naiara Bazin
ANNUAL MEETING:2014
Contents
About……………………………………………………………………………………….
Programme………………………………………………………………………………
Talk Abstracts…………………………………………………………………………..
Poster Titles…………………………………………………………………………..…
Directions…………………………………………………………………………………
Sponsors…………………………………………………………………………………..
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About YEN
The Young Embryologist Network was set up in 2008 by PhD students in the University
College London (UCL) Research Department of Cell & Developmental Biology under
the guiding hand of Dr Yoshiyuki Yamamoto. The purpose of the network came from a
desire to improve communication in the research environment for PhD and Post-Doc
embryologists.
Past Annual Young Embryologist Meetings have been hosted at University College
London and King's College London. They have being growing in success with over 100
participants from many UK and international institutions attending YEM:2013.
We aim to gather together PhD students and research scientists working in the field of
embryology and we hope that the Young Embryologist Network will continue to
expand and evolve in the future.
Network Aims
– To open lines of communication and create a diverse, interactive
research community for PhD students, Post-Doc and young PI
embryologists; essentially anybody who is at the bench.
– To encourage researchers to think across models and diverse
developmental systems.
– To help define and uncover the future direction of the field.
– To promote the importance, and help ensure the continuation of
basic research.
We hope to reach these aims through running the annual Young Embryologist
Meeting as well as series of seminars at rotating research institutions.
Acknowledgments
Thank you to all sponsors, invited speakers, judges and all the people involved in the
organisation of the 6th Young Embryologist Meeting (YEM:2014).
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Programme
9.30- 9.55
9.55
Registration
Welcome Address
First Session: Cell fate specification
Chair: Sara Pozzi
10.00
10.20
10.40
11.00
11.20
11.30
Dr Dang Vinh Do (Gurdon Institute, University of Cambridge)
A Genetic and Developmental Pathway from STAT3 to the OCT4NANOG Circuit is Essential for Maintenance of ICM Lineages in vivo
Mr Mubeen Goolam (PDN, University of Cambridge)
Satb1 regulates the early cell fate decisions in the preimplantation
mouse embryo
Miss Madeleine Pope (MRC Mammalian Genetics Unit)
Map3k4 is a dose dependent modifier of sensitivity to B6-YPOS
gonadal sex reversal in mice
Dr Rie Saba (Queen Mary University of London)
Sox17 expression in the cardiac progenitor cells regulates the
endocardium development
Dr Catarina Vicente (The Node Community Manager, Cambridge)
The Node: your community blog
Coffee Break & Poster Session
Second Session: Patterning the embryo
Chair: Hong-Ting Kwok
11.50
12.10
12.30
12.50
1.10 - 2.10
2
Miss Erica Namigai
The establishment of left-right asymmetry during spiralian
development in the serpulid annelid Pomatoceros lamarcki
Dr Daniele Soroldoni
A doppler effect in embryonic pattern formation
Mr Joseph Grice
Conserved Homeodomain Binding Syntax associated with
Hindbrain Patterning and Evolution
Miss Anneliese Norris
Morphogenesis of the chick eye: cellular and molecular
mechanisms
Lunch Break & Poster Session
Q&A Session: Working in Science: is it fun, well paid and rewarding?
Chair: Oleksandr Nychyk
2.10
Prof Mala Maini (Professor of Viral Immunology and Consultant
Physician, Division of Infection and Immunity, University College
London)
Prof Greg Towers (Professor of Molecular Virology and Senior
Wellcome Trust Biomedical Research Fellow, Division of
Infection and Immunity, UCL)
Third Session: Biomechanics
Chair: Matteo Mole
3.00
3.20
3.40
4.00
Miss Elina Tsichlaki
Regulation of nuclear size in mammalian embryos
Miss Elena Scarpa
Spatiotemporal dynamics of cadherin junctional complex and
actomyosin assembly during contact inhibition of locomotion
Dr Graham Sheridan
Investigating the role of mechanical cues in axon guidance
Coffee Break & Poster Session
The Sammy Lee Memorial Lecture
Chair: Naiara Bazin
4.20
Prof Bill Harris (Professor of Physiology, Development and
Neuroscience, University of Cambridge)
The forever embryonic eyes of frogs and fishes
5.20
Presentation of Talk and Poster Prizes
5:35
Closing Address
5:45
Reception at Marquis Cornwallis pub
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Talk Abstracts
Session 1: Cell fate specification
A Genetic and Developmental Pathway from STAT3 to the OCT4-NANOG Circuit is
Essential for Maintenance of ICM Lineages in vivo
Dang Vinh Do1, Barbara B. Knowles2, Davor Solter2 and Xin-Yuan Fu3
1 Gurdon
Institute, Cambridge; 2 Institute of Medical Biology, A*STAR, Singapore; 3 Department of
Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, USA.
Although it is known that OCT4-NANOG are required for maintenance of pluripotent cells
in vitro the upstream signals that regulates this circuit during early development in vivo
have not been identified. In this report, we demonstrate, for the first time, a hierarchical
genetic pathway from STAT3, which directly regulates the OCT4-NANOG circuit to induce
formation of the inner cell mass (ICM), the source of in vitro-derived ESCs. We now show
that STAT3 is highly expressed in mouse oocytes and becomes phosphorylated and
translocates to the nucleus in the 4-cell, and later stage, embryos. Using Lif-null embryos
we find STAT3 phosphorylation is dependent on LIF in 4-cell stage embryos. In blastocysts,
IL-6 acts in an autocrine fashion to ensure STAT3 phosphorylation, mediated by JAK1, a
LIF- and IL-6-dependent kinase. Using genetically engineered mouse strains to eliminate
Stat3 in oocytes and embryos, we firmly establish that STAT3 is essential for maintenance
of ICM lineages but not for ICM and trophectoderm (TE) formation. Indeed, STAT3 directly
binds to the Oct4 (Pou5F1) and Nanog distal enhancers, modulating their expression to
maintain pluripotency of mouse embryonic and induced pluripotent stem (iPS) cells. These
results provide a novel genetic model of cell-fate determination operating through STAT3
in the preimplantation embryo and in pluripotent stem cells in vivo.
Satb1 regulates the early cell fate decisions in the preimplantation mouse embryo
Mubeen Goolam, Magdalena Zernicka-Goetz
Department of Physiology, Development and Neuroscience, University of Cambridge.
Within the first four days of mouse embryonic development two cell fate decisions occur
which establish the correct morphological and molecular events to form an implanting
blastocyst. The first cell fate decision is a result of asymmetric divisions initiated at the 8to 16-cell stage which gives rise outer cells, the extraembryonic trophectoderm (TE), as
well as inside cells, the inner cell mass (ICM). The second cell fate decision segregates the
ICM into the epiblast (EPI), which will form the embryo proper, as well as the second
extraembryonic tissue, the primitive endoderm (PE). Through deep sequencing analyses
we have identified that Satb1 is differentially expressed between inside and outside cells
at the 16-cell stage. Depletion of both maternal and zygotic Satb1 altered ICM cell fate by
depleting the number of PE cells in the blastocyst. This phenotype could be rescued by coknockdown of Satb2 underlining the antagonistic effect of these two proteins. Clonal
knockdown of Satb1 indicated that blastomeres lacking Satb1 preferentially form EPI cells
within the ICM. Furthermore, increasing Satb1 levels resulted in the opposite phenotype
with an increase in PE cells and a subsequent decrease in EPI. Together these results show
a role for Satb1 in the preimplantation embryo.
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Map3k4 is a dose dependent modifier of sensitivity to B6-YPOS gonadal sex reversal
in mice
Madeleine Pope, Nick Warr, Gwenn-ael Carre, Pam Siggers, Andy Greenfield
MRC Mammalian Genetics Unit, Harwell, Oxfordshire.
In mammals the Y-linked gene Sry is a dominant male determinant, whose expression
initiates the cascade of events that drive differentiation of the testis. XY embryos lacking
Map3k4 exhibit delayed, insufficient expression of Sry and develop ovaries on the
C57BL/6J (B6) background. We have exploited a phenomenon termed B6-YPOS sex
reversal to investigate the relationship between Map3k4 and Sry in the mouse.
When the Y chromosome from Mus poschiavinus (YPOS) is introduced onto the B6
background all XY animals undergo complete or partial sex reversal associated with
delayed Sry expression. Gain-of-function experiments using a Map3k4 BAC transgene have
revealed that overexpression of Map3k4 is sufficient to restore testis determination in B6YPOS embryos. Furthermore, loss of a copy of Map3k4 results in more severe sex reversal.
Comprehensive transcriptional profiling shows that overexpressing Map3k4 in B6-YPOS
embryos partially restores the normal expression profile of Sry and establishes MAP3K4dependent control of Sry expression timing as a key player in B6-YPOS sex reversal. We are
currently exploring the epigenetic landscape of the Sry locus in B6-YB6 and B6-YPOS
gonads during the critical period of testis determination, in order to elucidate epigenetic
changes that could account for the differences in Sry expression underlying this
phenomenon and, more genrally, shed light on how signalling to the epigenome controls
cell fate.
Sox17 expression in the cardiac progenitor cells regulates the endocardium
development
Rie Saba1, Ioannis Kokkinopoulos1, Hidekazu Ishida1, Keiko Kitajima2, Chikara Meno2,
Yoshiakira Kanai3, Masami Azuma-Kanai4, Peter Koopman5, Yumiko Saga6, Yukio
Saijou7, Ken Suzuki1 and Kenta Yashiro1
1
Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and The London School
of Medicine and Dentistry, Queen Mary University of London, London; 2 Department of Developmental
Biology, Graduate School of Medical Sciences, Kyushu University, Japan; 3 Department of Veterinary
Anatomy, The University of Tokyo, Japan; 4 Center for Experimental Animal, Tokyo Medical and Dental
University, Japan; 5 Division of Molecular Genetics and Development, Institute for Molecular Bioscience,
The University of Queensland, Australia; 6 Division of Mammalian Development, Genetic Strains Research
Center, National Institute of Genetics, Japan; 7 Department of Neurobiology and Anatomy, The University of
Utah, USA.
During mouse development, cardiac progenitor cells (CPCs) in the heart field deliver many
types of cells to form cardiac tissues. Several CPC marker genes were identified, however
the regulatory mechanism underlying the fate determination has remained to be
elucidated. Our single cell cDNA analysis showed that a pan-endodermal marker Sox17
was expressed in some proportion of CPCs from the early bud stage, and that the
expression was highly correlated to that of the endothelial markers at the early somite
stage. Sox17-positive mesodermal cells appeared in heart field from early head fold stage
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to early somite stage, and contributed only to the endocardium in the heart tubule,
implying the cell-autonomic function in the endocardium development. We conducted the
gain of function and loss of function studies by the mice with BAC Nkx2-5(Sox17-ires-lacZBghA) transgene and Mesp1Cre/+/Sox17flox/flox alleles, respectively. The results showed
that Sox17 is not necessary or sufficient to induce the endocardial fate in CPCs, but can
bias it toward the endocardium in some extent. Further Mesp1Cre/+/Sox17flox/flox
embryos showed the typical defects of Notch signaling pathway and Notch1 was downregulated in the mutant heart tubule. Thus we conclude that Sox17 expression in CPCs
regulates the endocardium development via Notch signaling pathway.
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Session 2: Patterning the embryo
The establishment of left-right asymmetry during spiralian development in the
serpulid annelid Pomatoceros lamarcki
Erica Namigai, Sebastian Shimeld
Department of Zoology, University of Oxford, Oxford.
The establishment of body axes is a fundamental process of metazoan development.
However, how the left-right (LR) axis is established remains poorly understood, especially
in organisms outside of the Deuterostomia and Ecdysozoa. I am studying the mechanisms
underlying LR asymmetry establishment in the Lophotrochozoa using Pomatoceros
lamarcki, a serpulid annelid, as a model. To observe the first instance of symmetry
breaking, we are using live imaging to understand biases during axis establishment at early
cleavage stages, including the cellular architecture and dynamics of early spiral cleavage.
We have also sequenced the P. lamarcki genome, and key genes with a conserved function
in LR asymmetry (i.e. Nodal) are being analyzed. This research addresses key questions
concerning body axis establishment during spiralian development, and is valuable for
exploring the dynamic aspects of early development and to understand the evolution of LR
asymmetry within the Lophotrochozoa.
A doppler effect in embryonic pattern formation
Daniele Soroldoni1,3,4†, David J. Jörg2†, Luis G. Morelli1,5, David L. Richmond1, Johannes
Schindelin2,6, Frank Jülicher2, Andrew C. Oates1,3,4*
1Max
Planck Institute of Molecular Cell Biology and Genetics, Germany; 2Max Planck Institute for the Physics
of Complex Systems, Germany; 3MRC-National Institute for Medical Research, Mill Hill, UK; 4University
College London, London; 5Departamento de Física, FCEyN UBA and IFIBA, Ciudad Universitaria,
Argentina; 6University of Wisconsin at Madison, USA.
† equal contribution
In sequentially segmenting animal, the rhythm of segmentation is reported to be
controlled by the time scale of genetic oscillations that periodically trigger new
segment formation. However, here we present systematic, real-time measurements
of genetic oscillations in zebrafish embryos showing that the time scale of genetic
oscillations is not sufficient to explain the temporal period of segmentation. We find
that a second time scale, the rate of tissue shortening, contributes to the period of
segmentation through a Doppler effect. In addition, this contribution is modulated by
a gradual change in the oscillation profile across the tissue. We conclude that the
rhythm of segmentation is an emergent property controlled by the time scale of
genetic oscillations, the change of oscillation profile, and by tissue shortening.
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Conserved Homeodomain Binding Syntax associated with Hindbrain Patterning and
Evolution
Joseph Grice, Laura Doglio, Greg Elgar
Division of Systems Biology, National Institute for Medical Research, Mill Hill, London.
Understanding the function of regulatory elements is required to enrich our understanding
of development, disease and evolution. The sequence features that mediate these are
often unclear and the prediction of tissue-specific expression patterns from sequence
alone have produced only modest results. The hindbrain is a vertebrate shared-derived
structure segmented in to 7 rhombomeres, and offers an interesting model for the study
of spatially restricted enhancer activities.
We first identified a regulatory signature within conserved hindbrain enhancers (syntax),
consistent with published data, consisting of spatially co-occuring PBX, HOX and
MEIS/PREP transcription factor binding motifs. We then use this syntax to accurately
predict hindbrain enhancers in >90% of cases (61/64 tested elements). Finally,
mutagenesis of the sites causes ectopic expression, demonstrating their requirement for
segmental enhancer activities.
Our approach proves informative for the elucidation of motif grammars within conserved
elements. These data support the theory that hundreds of CNEs are constrained by their
functions as regulatory elements underlying the development of the hindbrain. It is likely
that sequences of this kind contributed to the co-option of new genes to the hindbrain
gene regulatory network during early vertebrate evolution by linking patterns of hox
expression to downstream genes involved in segmentation and patterning.
Morphogenesis of the chick eye: cellular and molecular mechanisms
Anneliese Norris & Andrea Streit.
Department of Craniofacial Development and Stem Cell Biology, King's College London, London.
The vertebrate eye has dual origin: the lens arises from the surface ectoderm, while the
retina, retinal pigment epithelium and optic nerve originates from the central nervous
system. The coordination of cell fate and morphogenetic processes is crucial to form a
functional eye. While cell fate decisions are a well studied, little is known about the
cellular mechanisms that control eye formation in amniotes, and how both relate to each
other. Here, we characterise the cellular events such as cell shapes from open neural plate
stages to optic vesicle formation, along with proliferation and orientated cell division, and
examined the contribution of each to the development of the eye. Using confocal
microscopy and live imaging we provide the first detailed analysis of these processes in
higher vertebrate. The main mechanisms that accompany epithelial morphogenesis are
under the control of the non-canonical planar cell polarity (PCP) Wnt pathway. We have
examined members of the PCP pathway, as well as Notch pathway components and we
find that these are expressed in a restricted pattern from open neural plate stages to optic
vesicle stages. We are currently investigating their role and how they interact. Ultimately
this will allow us to establish the molecular mechanisms that control vertebrate eye
morphogenesis and link them to cell fate allocation.
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Session 3: Biomechanics
Regulation of nuclear size in mammalian embryos
Elina Tsichlaki and Greg FitzHarris
University College London, London.
The mechanisms that dictate nucleus size are largely mysterious. Experiments in fission
yeast suggest that nuclear size is dictated by the size of the cell, whereas studies in
Xenopus indicate that nuclear import rates control nuclear volume. Here we set out to
investigate
factors
regulating
nucleus
size
in
mammalian
embryos.
We generated 3-dimensional confocal images to determine Nuclear/Cytoplasmic (N/C)
volume ratio. Fluorescent Recovery After Photobleaching (FRAP) of GFP-tagged nuclear
localization signal (GFP-NLS) was used to establish nuclear-import rates.
Micromanipulation was used to probe the influence of cell volume upon nuclear size.
Nuclear size decreases with successive cleavage divisions and N/C ratio was relatively
constant at any given developmental stage, suggesting a direct relationship between
nuclear and cell size. Experimental cytoplasmic removal reduced significantly nuclear size,
further validating this relationship. However, the N/C ratio set-point increases
progressively through development, revealing other factors present influencing nuclear
size. Nuclei in experimentally-generated embryos with ‘double-sized’ blastomeres were of
normal size, also suggesting a developmental programme involved. However, the rate of
nuclear import was identical through development revealing that nuclear import does not
dictate nuclear size. Rather, cell size in conjunction with developmentally-regulated
cytoplasmic factors dictate nuclear volume in mammalian embryos.
Spatiotemporal dynamics of cadherin junctional complex and actomyosin assembly
during contact inhibition of locomotion
Elena Scarpa1, Maddy Parsons2, Andras Szabo1, Roberto Mayor1
1
Department of Cell and Developmental Biology, UCL, London. 2Randall Division for Cell and Molecular
Biophysics, King's College London, London.
When mesenchymal cells interact they experience contact inhibition of locomotion (CIL):
cells enter in contact, stop moving, repolarize in opposite direction and separate. Neural
crest cells are a model to study CIL. During their migration, CIL is required for their
directional migration. CIL induces cell polarization by controlling protrusions via
RhoGTPases: when NCCs collide, RhoA activity increases at the contact while Rac1
decreases. These events depend on NCadherin.
Whether a cadherin adhesion complex is assembled during CIL and how cell-cell
interactions dynamically control Rho GTPases and actomyosin cytoskeleton has not yet
been characterized.
By imaging live Xenopus NCCs we show that a transient cadherin complex is formed upon
CIL. NCadherin, p120, alpha- and beta-catenin are recruited at NC-NC junctions when the
lamellipodia of two cells enter in contact. Live FRET imaging of collisions using RhoA and
Rac1 probes shows that RhoA is active at the junction until cells separate while Rac activity
remains higher at the cell leading edge. Finally, we investigated actomyosin organization:
during collisions actin and myosin are poorly recruited at the cell cortex underlying the
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junction, and contractile structures are assembled at the trailing edge of contacting cells
seconds before separation. These results suggest that upon CIL a functional cadherin
complex is organized in NCCs and Rho GTPases and actomyosin cytoskeleton are
dynamically regulated.
Investigating the role of mechanical cues in axon guidance
G.K. Sheridan1, H. Svoboda1, D. E. Koser1, A. Dwivedy1, A. J. Thompson1, M. P. Viana3,
L. F. Costa3, J. Guck2, C. E. Holt1, K. Franze1
1
Department of Physiology, Development and Neuroscience, University of Cambridge, 2Dept. of Physics,
University of Cambridge, Cambridge, 3Institute of Physics at Sao Carlos, Univ. of Sao Paulo, Sao Paulo, Brazil.
During Xenopus embryogenesis, development of the visual system involves the projection
of retinal ganglion cell (RGC) axons from eye primordia to correct synaptic contacts in the
optic tectum. There are well-characterised chemical cues that guide axons to their target
locations. During chemotactic migration, however, growing axons also physically interact
with their surrounding environment. Therefore, it is possible that mechanical interactions
could also influence their guidance to the tectum.
To probe RGC mechanosensitivity, we cultured Xenopus eye primordia ex vivo on
compliant hydrogels with increasing rigidities. We found clear morphological differences in
RGC axons grown on soft and rigid substrates. This includes differences in: 1) axon length;
2) axon velocity and directionality; 3) axon fasciculation and 4) growth cone turning on
stiffness gradients. This suggests that RGC axons are mechanosensitive which may impact
axon path-finding.
Using in vivo atomic force microscopy-based stiffness mapping of Xenopus exposed brains,
we found stiffness gradients along the path RGC axons grow. We reveal how RGC axons
migrate through relatively soft brain structures until they reach the more rigid optic
tectum, where they terminate. Exposing developing Xenopus embryos to inhibitors of
mechanosensitive ion channels causes RGC miswiring; suggesting that mechanical
properties of the extracellular environment may contribute to axon guidance in the
developing brain.
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Poster Titles
Ms. Maryam Anwar
King’s College London
A gene regulatory network for ear precursor specification
Dr Emanuele Azzoni
MRC Weatherall Institute of
Molecular Medicine
Kit-Ligand mediates the initial amplification of hematopoietic
progenitors
Miss Gabriela Carreno
UCL Institute of Child Health
Understanding the Role of SHH
Miss Anna Czarkwiani
University College London
Expression of embryonic skeletal development genes during
adult arm regeneration in the brittle star Amphiura filiformis
Mrs Diana Gold Diaz
UCL Institute of Child Health
Assisting research into human embryonic and fetal
development
Mr Alex Eve
MRC | National Institute for
Medical Research
Global transcriptome analysis reveals a novel role for Laminin
gamma-chain 3 in lymphangiogenesis.
Mr Stephen Fleenor
University of Oxford
Co-linear activation of intragenic promoters within Regulator
of G protein Signalling 3 (RGS3) drives successive isoformspecific expression and function throughout neuronal
maturation.
Mr Johannes Girstmair
University College London
The polyclad flatworm Maritigrella crozieri
Mr Mark Hintze
Department of Craniofacial
and stem cell biology, KCL
Integrating tissue and signals in sensory progenitor induction
Miss Shabana Khan
MRC National Institute for
Medical Research (NIMR)
Characterising the role of NeuroD6 in a novel subset of
midbrain dopaminergic (mDA) neurons
Dr Ioannis Kokkinopoulos
William Harvey Institute,
Barts and the London School
of Medicine & Dentistry
Characterisation of the First Heart Filed Cardiac Precursor Cells
Mr. Tiago Martins
UCL Institute of Child Health
Regulation of the mode of cell division and neurogenesis in
Zebrafish by CDK5RAP2.
Mr Joel May
Research Institute
Mammalian Genetic Unit,
MRC Harwell
Signal transduction Pathways in testis Determination
Miss Rebecca L. L. McIntosh
MRC Centre for
Developmental Neurobiology,
KCL
Basal Progenitors in the Zebrafish neural tube: Investigating
their origin and spatial organisation.
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Ms. Ramya Ranganathan
King’s College London
Molecular mechanisms in sensory placode formation
Dr Catherine Roberts
UCL Institute of Child Health
CYP26B1 is Required for Multiple Cardiovascular
Developmental Events.
Mr Jacob Ross
UCL Institute of Child Health
Integrins are required for synaptic transmission at the
neuromuscular junction
Mrs Scarlett Salter
Biomedical Research Unit in
Reproductive Health,
Warwick Medical School
Embryonic Proteases in Implantation
Miss Monica Tambalo
King’s College London
Towards a gene regulatory network for otic specification
Miss Katherine E Trevers
University College London
Towards a gene regulatory network for neural induction
Miss Elizabeth Ward
Dept. of Cell &
Developmental Biology, UCL
A role for the notochord in vertebral column development
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Directions to Venue
The conference takes place in the
UCL Anatomy Building, Gower Street,
London, WC1E 6BT. The J Z Young
Lecture Theatre, the Gavin de Beer
Lecture Theatre and the Histology
Teaching
Laboratory
are
the
conference venues within the
Anatomy Building.
The UCL Anatomy Building is located
on Gower Street and is outlined in
red on the map below.
The closest underground stations to
Gower Street are Russell Square
(Piccadilly Line), Goodge Street
(Northern Line) or Warren Street (Victoria or Northern Line). The nearest main line
stations are Euston and Kings Cross. All of these stations are within 5-15 minutes
walk.
A reception will be held afterwards at:
Marquis Cornwallis pub
31 Marchmont Street,
London, WC1N 1AP.
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Sponsored by:
Supported by
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