Characterization Of A Novel Human X-linked Gene RBMX, A Candidate For X-linked Mental Retardation
Funder
National Health and Medical Research Council
Funding Amount
$356,870.00
Summary
We recently discovered a novel gene (which we have called RBMX for RNA-binding protein, X chromosome) on the human X chromosome. Its function is quite unknown, but it is active in all tissues, and it has changed very little in evolution, so we think it must have an important function in human development. Genes with a similar sequence bind to RNA and convert it to its final active form, so RBMX may have a similar role. Other RNA-binding proteins are active in the brain, so we suspect that RBMX m ....We recently discovered a novel gene (which we have called RBMX for RNA-binding protein, X chromosome) on the human X chromosome. Its function is quite unknown, but it is active in all tissues, and it has changed very little in evolution, so we think it must have an important function in human development. Genes with a similar sequence bind to RNA and convert it to its final active form, so RBMX may have a similar role. Other RNA-binding proteins are active in the brain, so we suspect that RBMX may be involved in brain development and learning. The RBMX gene is also interesting because it has a copy called RBMY on the human Y chromosome, which is thought to have a critical (unknown) function in sperm production. Of particular note is our finding that RBMX maps to the long arm of the human X chromosome at Xq26. This is a region that contains several inherited mental retardation syndromes called X linked mental retardation (XLMR) which are carried by females and manifest in males. At least eight XLMR syndromes have been mapped to human Xq26. Several of the syndromes have characteristic skeletal and facial abnormalities, as well as a range of other anomalies.. We will completely characterise the human RBMX gene. As well as giving us fresh clues to its function, this will allow us to make a mouse strain that lacks the gene (knockout) so we can see whether it is critical for life, and if it is involved in brain development and learning. Identification of an XLMR gene coding for an RNA binding protein will shed light on the role of RNA metabolism in the brain, and the effect of disruptions of RNA processing on mental function. We will then screen the RBMX gene in families with XLMR syndromes, to look for RBMX mutations in patients which may cause XLMR. If mutations in RBMX cause one or more XMLR phenotypes, it will be possible to use this knowledge to diagnose the condition and detect carriers.Read moreRead less
A New Paradigm For SWI/SNF Chromatin Function; The ATPase Dependent Remodeler Is A Component Of The MeCP2 Complex
Funder
National Health and Medical Research Council
Funding Amount
$254,250.00
Summary
DNA methylation is a major determinant in the epigenetic silencing of many genes. The mechanisms underlying that targeting of DNA methylation and the consequence, that is, transcriptional silencing are relevant to human development and disease. Examples of the significance of alterations in the controls of DNA methylation and histone deacetylation in human disease include mental retardation (fragile X syndrome, Rett syndrome) and carcinogenesis. Evidence is emerging that a family of methylation ....DNA methylation is a major determinant in the epigenetic silencing of many genes. The mechanisms underlying that targeting of DNA methylation and the consequence, that is, transcriptional silencing are relevant to human development and disease. Examples of the significance of alterations in the controls of DNA methylation and histone deacetylation in human disease include mental retardation (fragile X syndrome, Rett syndrome) and carcinogenesis. Evidence is emerging that a family of methylation specific (methyl-CpG binding domain, MBD) proteins have the capacity to bind to methylated sequences and repress transcription. The mechanisms that target CpG methylation however still remain unclear. Furthermore, it is becoming increasingly evident that methyl-CpG binding proteins are not alone in silencing transcription and other epigenetic components are thought to influence transcription (namely, SWI-SNF activation complex). This grant proposal concentrates on our most recent work which demonstrates a new molecular mechanism of transcriptional repression extending the mechanism mediated by MeCP2. Our results are the first to show that the human SWI-SNF ATPase complex is a transcriptional repressor and is identified as part of the MeCP2-histone deacetylase repressor complex. This data extends the mechanistic link between DNA methylation, chromatin remodelling and transcriptional regulation. More importantly, the experimental findings could lead to a re-examination of the mechanistic basis behind MeCP2 transcriptional repression and epigenetic modification. Our findings suggest a new paradigm for SWI-SNF as a component of the MeCP2 methylation dependent silencing complex.Read moreRead less
The neocortex is the region of the brain that underlies all cognitive functions. Mental disorders, such as schizophrenia, occur when the communication between nerve cells in the neocortex breaks down. We propose to make electrical measurements from the thin processes of neurons that receive input from widely separated neocortical areas to understand how areas of the neocortex are functionally interlinked, with the ultimate aim to identify how these processes are disturbed in mental disorders.
SEZ6 AND NEURONAL CALCIUM SIGNALLING IN SYNAPSE DEVELOPMENT
Funder
National Health and Medical Research Council
Funding Amount
$617,685.00
Summary
Inappropriate development and function of neuronal circuits is a universal feature of neurological disorders of cognition such as Down syndrome, autism spectrum disorders and Fragile X mental retardation, epilepsy, schizophrenia and Alzheimer�s disease. In these diseases, neurons exhibit abnormal neuronal branches (dendrites) and abnormal connections on dendritic spines. This research is aimed at understanding the mechanisms controlling dendrite development that underpin proper neuronal wiring.
Identification Of Genes For X-linked Mental Retardation.
Funder
National Health and Medical Research Council
Funding Amount
$675,228.00
Summary
We propose to identify novel heritable causes of intellectual disability using 22 large and well-characterised families from Australia. In these families we have refined the location of the genetic defect to the chromosome X and excluded the contribution of all so far known genes. We will achieve this using the technology of massive parallel sequencing. At the completion of the project we will have identified novel causes of intellectual disability and devised tests to identify them.
Nuclear Factor One Genes Regulate Multiple Aspects Of Cerebral Cortex Development
Funder
National Health and Medical Research Council
Funding Amount
$526,878.00
Summary
To function, the brain must be formed correctly during embryonic development. We are investigating the embryonic development of the cerebral cortex, an area involved in high-order cognitive processing. Recently, we discovered that an important group of genes regulates cortical development, making it possible to study the underlying molecular mechanisms. The results will impact the prognosis and treatment of developmental brain disorders.