- Email: [email protected]
05-P007 X chromosome inactivation in murine extraembryonic development at post-implantation stages
S114
MECHANISMS OF DEVELOPMENT
1 2 6 (2 0 0 9) S1 1 3–S 11 9
environment’’ for efficient expression of tissue-specific genes via
approximately 20% of genes in S2 culture cells, and 10% in early
modulating high-order chromatin remodelling.
embryos, have initiated transcription but are transcriptionally paused. In both cases, the sets of paused genes are enriched for genes known to respond to developmental cues and environmen-
doi:10.1016/j.mod.2009.06.208
tal stimuli.There is mounting evidence that the Spt5 protein provides a key junction between developmental regulators of transcription and the core transcriptional elongation complex. 05-P004 – Withdrawn.
Mutations in Spt5 recovered from Drosophila and zebrafish that compromise its ability to cause transcriptional pausing result in discrete developmental defects, indicating that Spt5 mediates gene specific regulation. Spt5 acts as both a negative and a posi-
05-P005 Ddc, a candidate developmental gene in heart and its role in disease Adam Prickett, Ruth B. McCole, Reiner Schulz, Rebecca J. Oakey
tive regulator of elongation, and the switch between these activities at the promoter proximal checkpoint may provide a critical point of regulation by contextual transcription factors.We have characterized a missense mutation in Drosophila Spt5 (W049)
Department of Medical & Molecular Genetics, King’s College London,
that affects the transcription of a subset of genes during
London, United Kingdom
development. Expression of the gene even-skipped (eve) is
Dopa Decarboxylase (Ddc) is an enzyme that plays a fundamental role in the biosynthesis of catecholamine neurotransmitters and serotonin. A short form transcriptional variant of Ddc called Ddc_exon1a which originates from an alternative promoter at exon 1a, is highly expressed in the trabecular cardiomyocytes during development of pre-natal heart and is progressively silenced during post natal development. Ddc_exon1a has recently been shown by our group to be epigenetically regulated via geno-
directly subject to repression mediated by Spt5. Enhancerreporter constructs reproducing expression of specific stripes of eve expression are affected differentially by Spt5W049 indicating that Spt5 can regulate transcription in an enhancer-specific manner. The aim of our current work is to ascertain the molecular mechanisms by which contextual transcription factors regulate transcriptional pausing during development. doi:10.1016/j.mod.2009.06.211
mic imprinting in mouse heart in a tightly regulated tissue-specific and transcriptional variant-specific manner. Ddc and Ddc_exon1a show bi-allelic expression in all other tissues. We aim to show by analysing Ddc
+/
and Ddc
/+
knockout mice
05-P007 X chromosome inactivation in murine extraembryonic develop-
how ablation of Ddc_exon1a affects heart-specific development.
ment at post-implantation stages
We also will look at downstream target genes using microarray
Catherine Corbel, Patricia Diabangouaya, Edith Heard
analysis. We predict that the knockout may affect compaction
Institut Curie-CNRS UMR 3215, INSERM U934, Paris, France
of the myocardium during mid-gestation, which could lead to cardiomyopathies in adults. It has recently been shown that Ddc
X-chromosome inactivation (XCI) enables dosage compensa-
imprinting is controlled by epigenetic mechanisms via a differen-
tion between XX females and XY males. It is an essential process
tially methylated region located in CGI2 of adjacent Grb10,
that occurs during early female development. Our project aims to
another gene imprinted in development, CGI2 contains a putative
investigate the status and mechanism of XCI in female embryos
CTCF binding site. We present our current findings looking at
at post-implantation stages (E6.5-8). In the embryonic lineages of
expression patterns of Ddc_exon1a and Grb10 in the mouse
mice, X inactivation is random, with either the paternal (Xp) or
embryo using immunohistochemistry, insitu hybridization and
maternal chromosome being affected. In cells of extraembryonic
qPCR. Furthermore we look at the role of the insulator protein
tissues, imprinted X inactivation of the Xp chromosome is found.
CTCF using ChIP analysis and RNAi knockdown, to assay binding
We are interested in the potential differences between these two
and function of this protein at this gene locus.
types of XCI process during post-implantation development. The inactive state of the Xp in extraembryonic tissues is thought to
doi:10.1016/j.mod.2009.06.210
be less stable than in embryonic tissues. Recently it was shown that some genes are more prone to escape XCI than others in extraembryonic tissues (Patrat et al, PNAS, 106:5198, 2009). al., 2009. PNAS
05-P006
106, 5198). However little is known about the basis for this relative
Regulation of transcriptional elongation by spt5 during dro-
instability and such variability. We have set out to use an ’ex ‘ex
sophila development
vivo’ approach in order to evaluate the status of X-linked gene
Barbara Jennings1,2, Robert Harvey2, David Ish-Horowicz1
silencing/reactivation in frozen sections of post-implantation
1
Cancer Research UK, London Research Institute, London, United
Kingdom 2
UCL Cancer Institute, London, United Kingdom Transcription elongation has become recognised as a critical
point of control during the expression of many genes during development. For example, genome-wide screens for promoter proximal paused RNAP II in Drosophila have revealed that
embryos. The epigenetic marks on the inactive X and the nuclear organization of the X chromosome are being analyzed in different tissues at precise developmental stages. This analysis is being carried out both in wild type wild-type embryos and in mutants for various factors thought to be involved in XCI. doi:10.1016/j.mod.2009.06.212
MECHANISMS OF DEVELOPMENT
1 2 6 (2 0 0 9) S1 1 3–S 11 9
environment’’ for efficient expression of tissue-specific genes via
approximately 20% of genes in S2 culture cells, and 10% in early
modulating high-order chromatin remodelling.
embryos, have initiated transcription but are transcriptionally paused. In both cases, the sets of paused genes are enriched for genes known to respond to developmental cues and environmen-
doi:10.1016/j.mod.2009.06.208
tal stimuli.There is mounting evidence that the Spt5 protein provides a key junction between developmental regulators of transcription and the core transcriptional elongation complex. 05-P004 – Withdrawn.
Mutations in Spt5 recovered from Drosophila and zebrafish that compromise its ability to cause transcriptional pausing result in discrete developmental defects, indicating that Spt5 mediates gene specific regulation. Spt5 acts as both a negative and a posi-
05-P005 Ddc, a candidate developmental gene in heart and its role in disease Adam Prickett, Ruth B. McCole, Reiner Schulz, Rebecca J. Oakey
tive regulator of elongation, and the switch between these activities at the promoter proximal checkpoint may provide a critical point of regulation by contextual transcription factors.We have characterized a missense mutation in Drosophila Spt5 (W049)
Department of Medical & Molecular Genetics, King’s College London,
that affects the transcription of a subset of genes during
London, United Kingdom
development. Expression of the gene even-skipped (eve) is
Dopa Decarboxylase (Ddc) is an enzyme that plays a fundamental role in the biosynthesis of catecholamine neurotransmitters and serotonin. A short form transcriptional variant of Ddc called Ddc_exon1a which originates from an alternative promoter at exon 1a, is highly expressed in the trabecular cardiomyocytes during development of pre-natal heart and is progressively silenced during post natal development. Ddc_exon1a has recently been shown by our group to be epigenetically regulated via geno-
directly subject to repression mediated by Spt5. Enhancerreporter constructs reproducing expression of specific stripes of eve expression are affected differentially by Spt5W049 indicating that Spt5 can regulate transcription in an enhancer-specific manner. The aim of our current work is to ascertain the molecular mechanisms by which contextual transcription factors regulate transcriptional pausing during development. doi:10.1016/j.mod.2009.06.211
mic imprinting in mouse heart in a tightly regulated tissue-specific and transcriptional variant-specific manner. Ddc and Ddc_exon1a show bi-allelic expression in all other tissues. We aim to show by analysing Ddc
+/
and Ddc
/+
knockout mice
05-P007 X chromosome inactivation in murine extraembryonic develop-
how ablation of Ddc_exon1a affects heart-specific development.
ment at post-implantation stages
We also will look at downstream target genes using microarray
Catherine Corbel, Patricia Diabangouaya, Edith Heard
analysis. We predict that the knockout may affect compaction
Institut Curie-CNRS UMR 3215, INSERM U934, Paris, France
of the myocardium during mid-gestation, which could lead to cardiomyopathies in adults. It has recently been shown that Ddc
X-chromosome inactivation (XCI) enables dosage compensa-
imprinting is controlled by epigenetic mechanisms via a differen-
tion between XX females and XY males. It is an essential process
tially methylated region located in CGI2 of adjacent Grb10,
that occurs during early female development. Our project aims to
another gene imprinted in development, CGI2 contains a putative
investigate the status and mechanism of XCI in female embryos
CTCF binding site. We present our current findings looking at
at post-implantation stages (E6.5-8). In the embryonic lineages of
expression patterns of Ddc_exon1a and Grb10 in the mouse
mice, X inactivation is random, with either the paternal (Xp) or
embryo using immunohistochemistry, insitu hybridization and
maternal chromosome being affected. In cells of extraembryonic
qPCR. Furthermore we look at the role of the insulator protein
tissues, imprinted X inactivation of the Xp chromosome is found.
CTCF using ChIP analysis and RNAi knockdown, to assay binding
We are interested in the potential differences between these two
and function of this protein at this gene locus.
types of XCI process during post-implantation development. The inactive state of the Xp in extraembryonic tissues is thought to
doi:10.1016/j.mod.2009.06.210
be less stable than in embryonic tissues. Recently it was shown that some genes are more prone to escape XCI than others in extraembryonic tissues (Patrat et al, PNAS, 106:5198, 2009). al., 2009. PNAS
05-P006
106, 5198). However little is known about the basis for this relative
Regulation of transcriptional elongation by spt5 during dro-
instability and such variability. We have set out to use an ’ex ‘ex
sophila development
vivo’ approach in order to evaluate the status of X-linked gene
Barbara Jennings1,2, Robert Harvey2, David Ish-Horowicz1
silencing/reactivation in frozen sections of post-implantation
1
Cancer Research UK, London Research Institute, London, United
Kingdom 2
UCL Cancer Institute, London, United Kingdom Transcription elongation has become recognised as a critical
point of control during the expression of many genes during development. For example, genome-wide screens for promoter proximal paused RNAP II in Drosophila have revealed that
embryos. The epigenetic marks on the inactive X and the nuclear organization of the X chromosome are being analyzed in different tissues at precise developmental stages. This analysis is being carried out both in wild type wild-type embryos and in mutants for various factors thought to be involved in XCI. doi:10.1016/j.mod.2009.06.212