Biology Reference
In-Depth Information
CHAPTER ONE
Mechanisms and Dynamics of
Heterochromatin Formation
During Mammalian Development:
Closed Paths and Open Questions
Anas Fadloun
1
, André Eid
1
, Maria-Elena Torres-Padilla
2
Institut de G´n´tique et de Biologie Mol´culaire et Cellulaire, CNRS/INSERM U964, Universit´ de
Strasbourg, Illkirch, France
1
These authors contributed equally to this work.
2
Corresponding author: e-mail address: metp@igbmc.fr
Contents
1.
Introduction
2
2. Heterochromatin in the Early Embryo: A Rather Particular Environment
4
2.1 Dynamics of establishment of histone modifications during development
and function of their histone methyltransferases
6
2.2 DNA methylation and hydroxymethylation
17
2.3 Histone variants in heterochromatin in the embryo
20
2.4 Nuclear architecture in the mammalian embryo
21
3. Mechanisms of Heterochromatin Establishment and Inheritance
24
3.1 Heterochromatin establishment and centromeric chromatin
24
3.2 Establishment and assembly of constitutive heterochromatin
25
3.3 Maintenance of heterochromatin throughout the cell cycle
27
3.4 Targetting heterochromatin
28
3.5 Establishment of pericentric heterochromatin in mammals
31
3.6 Heterochromatin assembly: A more general RNA-related mechanism also
in mammals?
33
4. Concluding Remarks
34
Acknowledgments
36
References
36
Abstract
Early embryonic development in mammals is characterized by major changes in the
components of the chromatin and its remodeling. The embryonic chromatin and
the nuclear organization in the mouse preimplantation embryo display particular fea-
tures that are dramatically different from somatic cells. These include the highly specific
organization of the pericentromeric heterochromatin within the nucleus and the
suggested lack of conventional heterochromatin. We postulate that the plasticity of
