Upregulation Of Dyskerin Augments Telomerase Enzyme Activity In Haematopoietic Cells
Funder
National Health and Medical Research Council
Funding Amount
$372,049.00
Summary
The replication of cancer cells is unrestricted - they are immortal. Activation of the enzyme telomerase promotes immortalisation in 90% of human cancers. Conversely, telomerase deficiency causes life threatening blood disorders. We will investigate how one of the protein components of telomerase regulates enzyme activity in normal and leukaemic blood cells. The results will be valuable in the pursuit of new approaches to halting cancer cell replication and treating severe blood disorders.
Haemopoiesis is the process by which cells in the blood become committed to a specific cell type, mature and proliferate. The production of blood cells is a dynamic and constant process and if dysregulated will result in a number of different diseases and-or leukemias. Using a leukemic cell line we identified two genes, Hls5 and Hls7-Mlf1, involved in red blood cell maturation. In addition, both these genes have been implicated in cancer, Hls5 functions as a tumor suppressor and Mlf1 is associat ....Haemopoiesis is the process by which cells in the blood become committed to a specific cell type, mature and proliferate. The production of blood cells is a dynamic and constant process and if dysregulated will result in a number of different diseases and-or leukemias. Using a leukemic cell line we identified two genes, Hls5 and Hls7-Mlf1, involved in red blood cell maturation. In addition, both these genes have been implicated in cancer, Hls5 functions as a tumor suppressor and Mlf1 is associated with acute myeloid leukemia. Over-expression of either gene in immature red blood cells inhibited their development; Mlf1 had quite a profound affect on cell shape and size whereas Hls5 affected biochemical pathways with a decrease in haemoglobin production. We have identified binding partners of each of the molecules. Hls5 binds to FOG 1, a regulator of the red blood cell genes. In addition, Hls5 associates with Ubc9 and PIAS-1 - molecules involved in a novel form of gene regulation called sumoylation. Hls5 also regulates GATA-1 a key protein in red cell production. Wer have recently found that Mlf1 also regulates GATA-1. Importantly, we have demonstrated that Mlf1 binds DNA and other nuclear proteins and is able to affect gene transcription. This project will use cellular and biochemical assays as well as mouse models to elucidate the mechanisms by which these genes control the function of red blood cells.Read moreRead less
Characterization Of Novel Regulators Of Erythropoiesis
Funder
National Health and Medical Research Council
Funding Amount
$437,545.00
Summary
Mature red and white blood cells develop from hemopoietic stem cells in the adult bone marrow. The production of red blood cells is primarily controlled by the hormone erythropoietin (epo). The availability of this hormone in a recombinant form has aided in the treatment of numerous forms of anaemia resulting from kidney failure, malignancies, and AIDS. Previously we had identified that the protein Lyn must be present inside primitive red blood cells for epo to stimulate them to become mature fu ....Mature red and white blood cells develop from hemopoietic stem cells in the adult bone marrow. The production of red blood cells is primarily controlled by the hormone erythropoietin (epo). The availability of this hormone in a recombinant form has aided in the treatment of numerous forms of anaemia resulting from kidney failure, malignancies, and AIDS. Previously we had identified that the protein Lyn must be present inside primitive red blood cells for epo to stimulate them to become mature functional cells. We have identified six molecules which interact with Lyn in red blood cells. We have shown that amolecule called HS1 is important for epo function in individual red blood cells and now we plan to investigate its functions in whole animals, including mice that lack the HS1 gene. We have also shown that a molecule called Trip1 is important for red blood cell development. Interestingly, this molecule also interacts with the thyroid hormone receptor and can influence the effects of epo and thyroid hormone on red blood cell development. The interplay between these two hormones will be looked at in more detail both at the cell and whole animal levels in normal mice and those lacking the thyroid hormone receptor gene. The third Lyn binding molecule we isolated is a novel gene-we have named it ankyrin repeat protein in line with the molecules it is related to. This gene is expressed in red blood cells and we aim to investigate what role it plays in the development of these cells. The fourth gene is also novel and is closely related to another called AFAP-110, which can exert effects on the structure of a cell. Its role in red blood cell structure will also be investigated. Finally, the last two molecule we have identified are both novel and are unrelated to any other known proteins. As above, the effects of these two molecules on red blood cell development will be investigated.Read moreRead less
Characterization Of Haemopoietic Lineage Determining Genes
Funder
National Health and Medical Research Council
Funding Amount
$631,021.00
Summary
Haemopoiesis is the process by which blood cells develop from stem cells. This process is tightly regulated and is dependant upon the appropriate expression of genes at each developmental stage within various lineages. Our work focuses on two genes (Mlf1 and Hls5) that are involved in determining lineage commitment and affect the expression of key hemopoietic regulators. If these genes are aberrantly expressed leukemias and other blood disorders can develop.
Characterisation Of Novel Regulators Of The Haemopoeitic System.
Funder
National Health and Medical Research Council
Funding Amount
$381,680.00
Summary
All of the circulating blood cells (including red cells and white cells) develop from a single cell type, called the haemopoietic stem cell (HSC), found in the adult bone marrow. Normally, HSCs are gradually restricted to become only one cell type and once they have started down that pathway can no longer generate cells of another pathway (e.g. once HSC begin to develop into red blood cells, they cannot normally change their direction to become white cells). There are a few examples of mature ce ....All of the circulating blood cells (including red cells and white cells) develop from a single cell type, called the haemopoietic stem cell (HSC), found in the adult bone marrow. Normally, HSCs are gradually restricted to become only one cell type and once they have started down that pathway can no longer generate cells of another pathway (e.g. once HSC begin to develop into red blood cells, they cannot normally change their direction to become white cells). There are a few examples of mature cells, however, that have changed pathways. We have use one of these, the mouse J2E red cell changing into macrophages, to identify the genes involved in this process. Two of the genes we found, HLS5 and HLS7, are potentially important in lineage determination and normal blood development as well as the formation of blood cancers. This project aims to investigate the roles these genes play in blood development. Much of our work to date has focused on HLS7. The human equivalent of HLS7 was found by an American group independently of us as a gene which causes one type of blood cancer. We have shown HLS7 has dramatic effects on normal blood development and, together, these results clearly show the importance of this gene. Through our studies on how HLS7 works, we have identified another gene, M44, which may be important in regulation of HLS7 and also plan to investigate is function. Finally, HLS5 has similarities to a group of molecules called transcription factors which are known to be key regulators blood development. Clearly, analysis of this gene will further our knowledge in this field.Read moreRead less
Erythroid Molecular Cascades Involving The Tyrosine Kinase Lyn
Funder
National Health and Medical Research Council
Funding Amount
$496,500.00
Summary
Mature red and white cells develope from hemopoietic stem cells in the adult bone marrow. The production of red blood cells is primarily controlled by the hormone erythropoietin (Epo). The availability of this hormone in a recombinant form has aided in the treatment of numerous forms of anaemia resulting from kidney failure, malignancies, and AIDS. Previously we had identified that the protein Lyn must be present inside primitive red blood cells for Epo to stimulate them to become mature functio ....Mature red and white cells develope from hemopoietic stem cells in the adult bone marrow. The production of red blood cells is primarily controlled by the hormone erythropoietin (Epo). The availability of this hormone in a recombinant form has aided in the treatment of numerous forms of anaemia resulting from kidney failure, malignancies, and AIDS. Previously we had identified that the protein Lyn must be present inside primitive red blood cells for Epo to stimulate them to become mature functional cells. Recently, we have demonstrated that mice lacking the Lyn gene develope major problems with their red blood cells. We have identified several molecules which interact with Lyn in red blood cells. We have shown that a molecule called Cbp is important for Epo function in individual red blood cells and now we plan to investigate its function in whole animals. We have shown that a new molecule called Arp is important for red blood cell development. This protein moves in and out of the nucleus (where DNA is stored) and may be important in the regulation of genes needed for red blood cells. The third gene (AFAPbeta) is also novel and is closely related to another called AFAP-110, which can exert effects on the structure of a cell. Since red blood cells have to shrink considerably during their development, the role of AFAPbeta on red blood cell structure will also be investigated. From these experiments we should develop a much better understanding of how the production of red blood cells is controlled and how diseases of red blood cells (such as anaemia) occur.Read moreRead less