Mechanisms of DNA Methylation Defects at
the IGF2/H19 Imprinting Centre in Patients
with Foetal Growth Disorders
A thesis submitted in fulfilment of the requirements for the
degree of Master of Applied Science (Medical laboratory
Science)
Mansur Ennuri Shmela
B.V.Sc.
School of Medical Sciences
College of Science, Engineering and Health
RMIT
May 2009
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DECLARATION
I certify that except where due acknowledgement has been made, the
work is that of the author alone; the work has not been submitted
previously, in whole or in part, to qualify for any other academic award;
the content of the thesis is the result of work which has been carried out
since the official commencement date of the approved research
program; any editorial work, paid or unpaid, carried out by a third party is
acknowledged; and, ethics procedures and guidelines have been
followed.
Mansur Ennuri Shmela
09/05/2009
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ACKNOWLEDGMENTS
I would like to express my sincere gratitude to my supervisors:
Dr. Christine Gicquel, for her continued assistance and great
guidance throughout the entire period of my study and without her
support, this thesis would not exist.
Dr. Peter Roche, for his immediate help and enormous support
when I needed.
Ass/Prof. Assam El-osta, who gave me this opportunity to work
in his laboratory and for his great encouragement.
o Heartfelt thanks to all members of the epigenetic laboratory for
their excellent technical assistance and kind support.
o Special thanks to Dr. Julie Demars for her grateful assistance and
support during the last year.
o Many thanks to other people at Baker institute for their technical
assistance, especially Dr. Tye Dawood.
o Special thanks to my friends here in Australia for their kind
support.
o My thanks are due to my country (Libya) for providing with a
scholarship to undertake my study.
o Finally, I am grateful and thankful to my family in Libya for their
love and kind words of encouragement, specially my parents, who never
stop praying for me to be successful in my academic career and my life.
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IN THE NAME OF ALLAH THE MOST GRACIOUS
THE MOST MERCIFUL
To my father and mother,
Ennuri and Fatima,
To my brothers and sisters,
To my sister’s son and daughter,
Waleed and Sajeda,
I dedicate this simple work
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TABLE OF CONTENTS
Title ............................................................................................................ i
Declaration .............................................................................................. ii
Acknowledgments ................................................................................... iii
Table of contents ...................................................................................... v
List of figures .......................................................................................... vii
List of tables .......................................................................................... viii
Abbreviations ........................................................................................... ix
Abstract ................................................................................................... xi
1 INTRODUCTION .................................................................................. 1
1.1 Genomic imprinting ......................................................................... 2
1.1.1 Characteristics of imprinted genes ............................................. 3
1.1.2 Epigenetic marks of imprinted genes ......................................... 4
1.1.2.1 DNA methylation .................................................................. 4
1.1.2.2 Histone modifications and chromatin structure .................... 6
1.1.3 The imprinting cycle ................................................................... 8
1.2 The IGF2/H19-ICR1 domain .......................................................... 11
1.2.1 Overview of IGF system .......................................................... 12
1.2.2 The IGF2 gene ......................................................................... 14
1.2.3 The H19 gene .......................................................................... 15
1.2.4 The epigenetic regulation of the reciprocal imprinting of the
IGF2 and H19 genes .............................................................. 16
1.2.4.1 Structure and chromatin organization of the ICR1
domain ............................................................................... 16
1.2.4.2 The CTCF protein .............................................................. 18
1.2.4.3 Other factors possibly involved in the control of imprinting
at ICR1............................................................................... 21
1.3 Role of the 11p15 region in development and disease .................. 22
1.3.1 Mouse models ......................................................................... 23
1.3.2 Human models ......................................................................... 23
1.3.2.1 Foetal growth disorders ..................................................... 23
1.3.2.2 Genetics of foetal growth disorders ................................... 24
1.4 Aims of the research ..................................................................... 28
