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
Transcriptional Control Of Blood Vessel Development By Sox18
Funder
National Health and Medical Research Council
Funding Amount
$468,564.00
Summary
Blood vessels play an essential role in maintaining the supply of nutrients to every organ and tissue in the body. Improper development of blood vessels in the embryo can compromise survival of the embryo, and defects in the ability of blood vessels to grow, regenerate and adapt to change during adult life can be life-threatening. The growth of new blood vessels (angiogenesis) is also an important factor in the ability of solid tumours to grow during the progression of cancer. It is therefore of ....Blood vessels play an essential role in maintaining the supply of nutrients to every organ and tissue in the body. Improper development of blood vessels in the embryo can compromise survival of the embryo, and defects in the ability of blood vessels to grow, regenerate and adapt to change during adult life can be life-threatening. The growth of new blood vessels (angiogenesis) is also an important factor in the ability of solid tumours to grow during the progression of cancer. It is therefore of fundamental importance in the health sciences to gain an understanding of how blood vessels form and regenerate. As a result of our collaborative research efforts, we have discovered a gene, Sox18, that appears to regulate blood vessel development by controlling the formation and-or behaviour of endothelial cells, which line the blood vessels and make them impermeable. Our research so far indicates that MICE WITH DEFECTS IN SOX18 DIE FROM VASCULAR DEFECTS, underlining the importance of this gene. THIS PROJECT IS CONCERNED WITH FINDING OUT HOW SOX18 WORKS - exactly what goes wrong in mice lacking this gene, whether Sox18 can influence endothelial cell behaviour in cell culture, how Sox18 comes to be active in endothelial cells, what genes are switched on by Sox18, and what genes Sox18 co-operates with in its role in endothelial cells. The answers to these questions will not only provide fundamental basic information about how blood vessels development is controlled, but also sow the seeds for possible future therapies in which blood vessel development could be stimulated (eg in wound healing) or suppressed (eg in tumour progression) through pharmaceutical intervention.Read moreRead less
The Role Of Sox8 In Sex Determination And Human Disease
Funder
National Health and Medical Research Council
Funding Amount
$211,527.00
Summary
We have discovered a new gene called Sox8. This gene is very closely related to another gene, Sox9, that is known to be a critical factor in determining whether an embryo develops as a male or female by specifying whether the embryo makes testes or ovaries. We have found that Sox8, like Sox9, is active in the cell type in fetal testes known to be important for the development of maleness, at around the time when the male-female decision is being made. We therefore believe that Sox8 is an importa ....We have discovered a new gene called Sox8. This gene is very closely related to another gene, Sox9, that is known to be a critical factor in determining whether an embryo develops as a male or female by specifying whether the embryo makes testes or ovaries. We have found that Sox8, like Sox9, is active in the cell type in fetal testes known to be important for the development of maleness, at around the time when the male-female decision is being made. We therefore believe that Sox8 is an important part of the genetic chain of events leading to normal male development. We aim to study how Sox8 exerts its effects on male development. We have also found that in humans, Sox8 is located in a chromosomal region associated with a developmental disease syndrome characterized by mental retardation, facial defects and anomalies of male sexual development. Sox8 is active in mouse embryos in all the tissues affected by the human disease. We believe defects in SOX8 in humans are largely responsible for this disease, called ATR-16 syndrome. We will test whether patients with ATR-16 have defects involving SOX8 in their DNA in order to test this theory. In summary, we believe we have found a new human disease gene which will further our understanding of how developmental diseases arise in the embryo. In addition, this work will shed light on the process of sexual development, a significant healthcare problem in view of the fact that defects in sexual development are among the most common forms of birth defects.Read moreRead less
Control Of Blood Vessel Development By SOX Transcription Factors
Funder
National Health and Medical Research Council
Funding Amount
$495,750.00
Summary
Cardiovascular disease is Australia s greatest health problem, with an estimated 3 million Australians suffering a spectrum of conditions from hypertension through to heart failure. Improper development of blood vessels in the embryo can compromise survival of the embryo, and predispose patients to vascular disease after birth. The growth of new blood vessels (angiogenesis) is also an important factor in the ability of solid tumours to grow during the progression of cancer. It is therefore of fu ....Cardiovascular disease is Australia s greatest health problem, with an estimated 3 million Australians suffering a spectrum of conditions from hypertension through to heart failure. Improper development of blood vessels in the embryo can compromise survival of the embryo, and predispose patients to vascular disease after birth. The growth of new blood vessels (angiogenesis) is also an important factor in the ability of solid tumours to grow during the progression of cancer. It is therefore of fundamental importance in the health sciences to gain an understanding of how blood vessels form and regenerate. We discovered a gene, Sox18, that appears to regulate blood vessel development by controlling the formation and-or properties of endothelial cells, which line the blood vessels and make them impermeable. Our research so far indicates that MICE WITH DEFECTS IN SOX18 DIE FROM VASCULAR DEFECTS, underlining the importance of this gene. THIS PROJECT IS CONCERNED WITH FINDING OUT HOW SOX18 WORKS - exactly what goes wrong in mice lacking this gene, whether Sox18 can influence endothelial cell behaviour in cell culture, how Sox18 comes to be active in endothelial cells, what genes are switched on by Sox18, and what genes Sox18 co-operates with in its role in endothelial cells. The answers to these questions will not only provide fundamental basic information about how blood vessels development is controlled, but also sow the seeds for possible future therapies in which blood vessel development could be stimulated (eg in wound healing) or suppressed (eg in tumour progression) by drug treatments.Read moreRead less
Identifying The Pathological Mechanism Of Polyalanine Expansion Mutations In The X-linked Hypopituitarism Gene SOX3
Funder
National Health and Medical Research Council
Funding Amount
$402,846.00
Summary
Mental retardation (MR) is a debilitating disorder which affects 1-3% of the population. In many cases, MR results from changes (mutations) in genes which regulate the development of the brain before birth. We are studying families with an inherited form of MR termed X-linked Hypopituitarism (XH) in which only boys are affected. In addition to intellectual disability, boys with XH also have poor pituitary function resulting in short stature and slow metabolism. In severe cases, where the pituita ....Mental retardation (MR) is a debilitating disorder which affects 1-3% of the population. In many cases, MR results from changes (mutations) in genes which regulate the development of the brain before birth. We are studying families with an inherited form of MR termed X-linked Hypopituitarism (XH) in which only boys are affected. In addition to intellectual disability, boys with XH also have poor pituitary function resulting in short stature and slow metabolism. In severe cases, where the pituitary has failed to form completely, these babies are extremely ill and in some instances do not survive. We have previously shown that XH is due to an unusual change in the SOX3 gene in which the number of consecutive alanine residues is increased above a critical threshold (polyalanine expansion mutations). Similar mutations have recently been identified in several other genes that also cause severe birth defects. However, little is currently known about how polyalanine expansion mutations cause these disorders. The overall aim of this proposal is generate a mouse model for this disorder. Analysis of these mice will help us to answer many unresolved questions about this disorder including: How does the mutant protein cause this disorder? Which parts of the brain and pituitary are affected and how is their function altered? How does the mutant protein affect other genes and proteins in the cell? Ultimately, we hope that this mouse model will help us to develop new and improved therapies for XH and other disorders that are caused by alanine expansion mutations.Read moreRead less