European Human Genetics Conference 2007 June 16 – 19, 2007 ...

Molecular and biochemical basis of disease
phenotype, whereas homozygous inheritance leads to intermediate βthalassemia.
As a result, the compound heterozygosity of Hb Knossos
with IVSII-745 appears as the cause of the beta-thalassemia major
phenotype in our case. In conclusion, we suggest that combination of
these mutations in beta-globin gene is important in expression of betathalassemia
major phenotype in a marriage between a beta-thalassemia
carrier and a person who has Hb Knossos and its like some other
silent beta-thalassemia mutations are not associated with an elevated
HbA2 level.
P0670. Genetic diagnosis in the Birt-Hogg-Dubé syndrome
S. Giraud 1 , E. Chanard 1 , C. Bourdin 1 , S. Lefebvre 1 , I. Coupier 2 , D. Bessis 3 ,
O. Caron 4 , A. Hovnanian 5 , P. Delobre 1 , M. Avril 6 , A. Calender 1 , S. Richard 7,8 ,
French NCI “Inherited Kidney Cancer Network”;
1 Hôpital E. Herriot, Hospices Civils de Lyon, Lyon, France, 2 Hôpital Arnaud de
Villeneuve, Montpellier, France, 3 Hôpital Saint Eloi, Montpellier, France, 4 Hôpital
Hautepierre, Strasbourg, France, 5 Hôpital Purpan, Toulouse, France, 6 Hôpital
Cochin-Tarnier, Paris, France, 7 Hôpital de Bicêtre, Le Kremlin-Bicêtre, France,
8 EPHE-FRE2939, Institut Gustave Roussy, Villejuif, France.
Birt-Hogg-Dubé (BHD) syndrome is an inherited autosomal dominant
genodermatosis characterized by predisposition to cutaneous fibrofolliculomas,
lung cysts leading to pneumothorax and renal cell carcinomas.
The age-dependent penetrance and the great variability of the
clinical manifestations even within a given family suggest that BHD remains
underdiagnosed. The disease is caused by heterozygous germline
mutations in the BHD gene, encoding fibrofolliculin. Mutations are
identified in 85% of BHD patients. All mutations previously reported
putatively lead to protein truncation. More than 50% of mutations are
frameshift located in a C-poly-tract in the exon 11.
We have performed genetic diagnosis with DNA sequencing of BHD
and Multiplex PCR/Liquid Chromatography for detection of rearrangement
of this gene. We have analyzed 100 unrelated index cases with
suspected or confirmed clinical diagnosis of BHD syndrome and identified
14 germline BHD different mutations in 24 probands: 8 frameshifts
with two recurrent mutations (one duplication in exon 11 was found in
9 patients, one deletion in the exon 9 in three patients), 3 nonsense
mutations, two splice site mutations, one missense mutation and one
rearrangement. Ten were novel mutations including the missense mutation
and the large rearrangement that have not yet been described
in BHD. Presymptomatic diagnosis was then performed in 47 relatives
revealing 34 gene carriers at whom clinical surveillance including kidney
imaging has been proposed.
We discuss our results according to patients’ clinical manifestations
and clinical indications of research of BHD mutations.
P0671. The Bloom‘s syndrome helicase interacts with the MutS
homolog, MSH4, during meiosis
F. Lespinasse, F. Lahaye, V. Paquis-Flucklinger, S. Santucci-Darmanin;
Equipe M3R UMR CNRS 6543, Nice, France.
Bloom’s syndrome (BS) is a recessive human genetic disorder characterized
by marked genetic instability associated with a greatly increased
predisposition to cancers of most types. The gene mutated in
BS encodes a 3’-5’ DNA helicase (BLM) identified as a member of the
RecQ family. BLM is involved in the cellular response to DNA damage
and stalled replication forks. Moreover, several studies support a role
of BLM during meiosis and it is noteworthy that human males homozygous
for BLM mutation are infertile. However, the specific function
of BLM during meiosis remains unclear. Here, we provide biochemical
evidence indicating that BLM interacts with MSH4 during meiotic prophase
I. These data are consistent with cytological analyses showing
that both BLM and MSH4 foci are located on chromosome cores at
the same stages of the meiotic prophase I. MSH4 is a meiosis-specific
MutS homolog known to participate to several steps of meiotic recombination
process. MSH4 acts first at the step of homologous chromosomes
synapsis and, in ensuing steps, to promote meiotic crossovers.
Based on the biochemical properties of BLM and MSH4, we consider
the possibility that interaction between BLM and MSH4 may have implications
in the regulation of meiotic recombination events which is
crucial since impaired meiotic recombination process may result in
nondisjunction of homologous chromosomes at the first meiotic division
and formation of aneuploid germ cells.
P0672. Semax exerts vasotropic and neuroprotective effects in
experimental brain ischemia
V. V. Stavchansky 1 , L. V. Dergunova 1 , V. V. Yuzhakov 2 , T. V. Tvorogova 3 , V. I.
Skvortsova 3 , S. A. Limborska 1 ;
1 Institute of Molecular Genetics RAS, Moscow, Russian Federation, 2 Medical
Radiology Research Center RAMS, Obninsk, Russian Federation, 3 Institute of
Stroke RSMU, Moscow, Russian Federation.
We have analyzed the effects of Semax ( synthetic peptide Met- Glu-
His-Phe-Pro-Gly-Pro; its N-terminus represents a fragment of adrenocorticotropic
hormone - ACTH 4-7) and its C- terminal fragment
Pro-Gly-Pro (PGP) on functional morphology and proliferative activity
of cells from different cerebral regions of the rats subjected to global
brain ischemia. The study was carried out on brain of 2-month-old male
Wistar rats (n=45). After 15 minutes of irreversible bilateral common
carotid artery occlusion the animals were exposed to intraperitoneal injection
of Semax, PGP or 0,9% NaCl. The repeated introductions were
made at 1h, 4h and 8h after operation. Animals were decapitated at 30
min and 24 h after operation. Intact and sham-operated animals were
used as a control group. The sections were stained with hematoxylin
and eosin for histological analysis. Murine monoclonal antibodies to
PCNA (proliferating cell nuclear antigen) were used for immunostaining
of proliferating cells. In intact animals, comparative morphofunctional
analysis of effect of Semax or PGP has indicated that both peptides
have exerted vasotropic effects based on activation of capillary
network. The increase of intensity of immunopositive reaction of proliferating
cells demonstrates trofic action of Semax on ependyma of ventricles,
cells of blood-brain barrier and neuroglia. In this study, among
these investigated peptides only Semax has manifested neuroprotective
action on animals with acute stroke. Semax decreases ischemic
injury of neurons and prevents progress of local foci of destruction of
neuronal tissue. Furthermore, signs of vascular stasis decrease in the
ischemized rat brains under Semax trearment.
P0673. Estrogen receptor (ER) beta2 negatively regulates the
transactivation of ERα in human breast cancer cells
C. Zhao 1 , J. Matthews 2 , M. Tujague 1 , J. Wan 3 , A. Ström 1 , G. Toresson 1 , E. W-F
Lam 4 , G. Cheng 1 , J. Gustafsson 1 , K. Dahlman-Wright 1 ;
1 Karolinska Institute, Stockholm, Sweden, 2 University of Toronto, Toronto, ON,
Canada, 3 KTH-Royal Institute of Technology, Stockholm, Sweden, 4 Imperial
College London, London, United Kingdom.
Estrogens, by binding to and activating two estrogen receptors (ERs),
ERalpha and ERbeta, are critically involved in the development of the
mammary gland as well as breast cancer. An isoform of ERbeta, ERbeta2
(also called ERbetacx), with an altered C-terminal region, is coexpressed
with ERalpha in many human breast cancers. In this study,
we generated a stable cell line from MCF7 breast cancer cells expressing
an inducible version of ERbeta2, along with endogenous ERalpha,
and examined the effects of ERbeta2 on the ERalpha protein levels
and function. We showed that ERbeta2 inhibited ERalpha-mediated
transactivation via ERE and AP-1 sites of reporter constructs as well
as the endogenous genes pS2 and MMP-1. Chromatin immunoprecipitation
(ChIP) assays revealed that ERbeta2 expression caused a
significant reduction in the recruitment of ERalpha to both the pS2 and
MMP-1 promoters. Furthermore, ERbeta2 expression induced proteasome-dependent
degradation of ERalpha. The inhibitory effects of ERbeta2
on ERalpha activity were further confirmed in HEK293 cells that
lack functional endogenous ERs. We also demonstrated that ERbeta2
can interact with ERalpha both in vitro and in mammalian cells which
is compatible with a model where ERbeta2/ERalpha heterodimers are
targeted to the proteasome. Finally, in human breast cancer samples,
we observed that expression of ERbeta2 significantly correlated with
ERalpha-negative phenotype. Our data suggest that ERbeta2 could
influence ERalpha-mediated effects relevant for breast cancer development
including hormone responsiveness.
P0674. STAT6 and ADAM33 single nucleotide polymorphism in
association with Bronchial asthma
F. Kopriva1 , R. Vodicka1 , R. Vrtel1 , L. Dusek2 , M. Godava1 , M. Markova1 , J.
Bohmova1 , J. Zavodska1 , A. Plocova1 , E. Schneiderova1 , E. Krejcirikova1 ;
1University Hospital and Palacky University Olomouc, Olomouc, Czech Republic,
2CBA Masaryk University, Brno, Czech Republic.
Bronchial asthma is one of the most frequent childhood chronic ailments,
defined on the basis of epidemiological, physiological, patho-
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