Defects in sexual development in the human embryo result in some of the most common forms of birth defects, which have profound physiological and psychosexual ramifications for the afflicted individuals. A fuller understanding of the causes of these defects may lead to improved counseling and perhaps also therapeutic possibilities. This project is aimed at finding and studying the genes that control whether an embryo develops as a male or a female, and the genes that are responsible for proper d ....Defects in sexual development in the human embryo result in some of the most common forms of birth defects, which have profound physiological and psychosexual ramifications for the afflicted individuals. A fuller understanding of the causes of these defects may lead to improved counseling and perhaps also therapeutic possibilities. This project is aimed at finding and studying the genes that control whether an embryo develops as a male or a female, and the genes that are responsible for proper development of the gonads, organs that control an individual's sexual development. It is thought that a genetic chain of events is important for gonadal development, and we aim to find the missing links of that chain and to work out how they fit together.Read moreRead less
Functional Analysis Of Candidate Sex-determining And Gonadal Development Genes
Funder
National Health and Medical Research Council
Funding Amount
$503,500.00
Summary
This project is aimed at finding and studying the genes that control whether an embryo develops as a male or a female, and the genes that are responsible for proper development of the gonads, organs that control an individual's sexual development. It is thought that a genetic chain of events is important for gonadal development, and we aim to find the missing links of that chain and to work out how they fit together, as well as how genetic defects can lead to disorders of sexual development. Def ....This project is aimed at finding and studying the genes that control whether an embryo develops as a male or a female, and the genes that are responsible for proper development of the gonads, organs that control an individual's sexual development. It is thought that a genetic chain of events is important for gonadal development, and we aim to find the missing links of that chain and to work out how they fit together, as well as how genetic defects can lead to disorders of sexual development. Defects in sexual development in the human embryo not only result in some of the most common forms of birth defects but also have profound physiological and psychosexual ramifications for the afflicted individuals. A fuller understanding of the causes of these defects will lead to improved patient management.Read moreRead less
Defects of the internal and external genitalia are among the most common birth defects in babies (1 in 4,000 births) yet the aetiology in many cases is unclear. We will compare and contrast the mouse with a unique animal model the tammar wallaby to investigate the control of ovarian differentiation during early fetal and postnatal life. The gonad is unusual in that two completely different organs arise from the same precursor tissues, so that errors in development lead to intersexual phenotypes. ....Defects of the internal and external genitalia are among the most common birth defects in babies (1 in 4,000 births) yet the aetiology in many cases is unclear. We will compare and contrast the mouse with a unique animal model the tammar wallaby to investigate the control of ovarian differentiation during early fetal and postnatal life. The gonad is unusual in that two completely different organs arise from the same precursor tissues, so that errors in development lead to intersexual phenotypes. Some intersexual conditions are the result of inappropriate exposure to hormones during fetal life, and others are due to spontaneous or inherited gene mutations. About 5-10% of ovarian cancer cases, that affect 1 in 8000 Australian women, are due to the inheritance of a faulty gene. We will use comparative analysis and an inducible sex reversal system to understand the way gene expression and hence tissue differentiation is altered between male and female during the formation of the ovary versus the testis. This will inform us about the causes and consequences of normal and abnormal sexual development, infertility and gonadal malignancies.Read moreRead less
Copy Number Analysis Of Patients With Gonadal Abnormalities Using High Density Microarrays And MLPA
Funder
National Health and Medical Research Council
Funding Amount
$311,187.00
Summary
Congenital conditions in which development of the gonads or anatomical sex is abnormal are surprisingly common. The underlying cause of these problems is most often the failure of genes responsible for proper development of testes or ovaries. Only a small proportion of patients can be explained by mutations in known gonad determining genes. We will analyse DNA from these patients on very high density microarrays to identify new genes that cause abnormalities in testis and ovary development.
Role Of Human SRY And SOX9 In Sex Determination And Disease.
Funder
National Health and Medical Research Council
Funding Amount
$308,820.00
Summary
The decision to develop as a male or female is controlled by a genetic pathway which culminates in the development of a testis or an ovary in the human embryo. The correct development of these reproductive organs depends on the coordinated activation of a network of genes by transcription factors. Analysis of patients with defective reproductive organs has shown that a number of these individuals have mutations in two transcription factor genes, SRY and SOX9. Mutations in SRY (Swyer syndrome) or ....The decision to develop as a male or female is controlled by a genetic pathway which culminates in the development of a testis or an ovary in the human embryo. The correct development of these reproductive organs depends on the coordinated activation of a network of genes by transcription factors. Analysis of patients with defective reproductive organs has shown that a number of these individuals have mutations in two transcription factor genes, SRY and SOX9. Mutations in SRY (Swyer syndrome) or SOX9 (autosomal sex reversal-campomelic dysplasia) cause the development of female reproductive structures in individuals with male chromosomes. Towards understanding how SRY and SOX9 work to determine sex, we have identified four proteins that interact with SRY and SOX9. Two of these proteins, called importin-beta and calmodulin have a role in transporting SRY and SOX9 into the cell nucleus. The other two proteins, called PC4 and HSP70, appear to be involved in co-operating with SRY and-or SOX9 to turn genes on. In the developing mouse testis, a large number of genes are expressed at the time immediately following the expression of SRY and SOX9. We will identify which of these 50 genes are being directly switched on or off by SRY and SOX9 during sex determination. These studies will identify how SRY and SOX9 direct normal testis formation and how mutations cause developmental defects. Also, by unravelling the testis formation pathway, we expect to identify new genes involved in sexual dysmorphology syndromes.Read moreRead less
A Y CHROMOSOME MODEL FOR THE SEX DETERMINING FUNCTION OF THE HUMAN ATRX GENE
Funder
National Health and Medical Research Council
Funding Amount
$272,131.00
Summary
Human sex determination is controlled by a genetic pathway which culminates in the development of a testis or an ovary in the human embryo. At the head of this pathway is the master switch gene SRY on the Y chromosome, which controls a cascade of other genes critical for switching on testis development. Several other genes have been identified by clinical mutations which reverse sex of XY embryos. One sex reversing gene is ATRX on the human X chromosome. Mutation in ATRX causes XY embryos to dev ....Human sex determination is controlled by a genetic pathway which culminates in the development of a testis or an ovary in the human embryo. At the head of this pathway is the master switch gene SRY on the Y chromosome, which controls a cascade of other genes critical for switching on testis development. Several other genes have been identified by clinical mutations which reverse sex of XY embryos. One sex reversing gene is ATRX on the human X chromosome. Mutation in ATRX causes XY embryos to develop as females, as well as causing many unrelated disorders such as alpha-thalassemia. ATRX seems to be a transcription factor that controls the activity of other genes, but it is difficult to understand how it functions because it is active in all parts of the body and mutation has many different effects in humans. However, we recently discovered that in marsupial mammals that this gene has a copy on the Y chromosome (ATRY) as well as the X (ATRX). Remarkably, there is a division of labour between ATRY, which acts only in developing gonads, and ATRX, which is active everywhere else. This testis-specific ATRY gene may reveal how ATRX interacts with other genes to make a testis, without the complications of its action in other tissues. We will therefore clone and characterize ATRX-Y and its protein product to find out when and where it acts in the sex determining pathway. We will use very large cloned pieces of the marsupial genome to discover elements controlling the testis-specific expression, and we will identify the interactions of ATRY with other proteins. The testis determination pathway is a good model for the differentiation of other human organs. Our work on ATRY will show us how this class of transcription factors is activated in different tissues during development, and how it controls other genes. This will lead to a better understanding of the genetic control of human organogenesis and the effects of mutation on human development.Read moreRead less
Testis To Ovary: Hormonal Control Of Differentiation
Funder
National Health and Medical Research Council
Funding Amount
$803,379.00
Summary
We know very little of the genes that control development of the ovary in female fetuses; most study has focused on the formation of the testis in males. We will use a novel experimental model, a marsupial, where by hormonal treatment of developing males we can switch off testis formation and activate the ovarian pathway. These studies will potentially shed new light on the causes of reproductive diseases including ovarian cancer, as well as clarifying the basic biological processes that guide f ....We know very little of the genes that control development of the ovary in female fetuses; most study has focused on the formation of the testis in males. We will use a novel experimental model, a marsupial, where by hormonal treatment of developing males we can switch off testis formation and activate the ovarian pathway. These studies will potentially shed new light on the causes of reproductive diseases including ovarian cancer, as well as clarifying the basic biological processes that guide formation of the ovary.Read moreRead less