SRC FAMILY PROTEIN TYROSINE KINASES IN HEMATOPOIESIS

细胞质酪氨酸激酶在细胞内信号传导中起关键作用 在造血细胞中。 研究这些激酶在血液中的功能 我们已经在胚胎干细胞中使用基因靶向技术， 在几个SEC家族基因中有突变 我们已经集中在 hck、fgr、林恩和src基因，由这些基因编码的激酶已经被 参与由细胞因子，脂多糖， 以及IgM和Fc受体的交联。 单核细胞的分析和 来自hck-/-小鼠的巨噬细胞显示出吞噬能力降低 乳胶头 然而，没有发现其他髓系细胞表型 提示Hck的缺失可被其他Src家族所补充 激酶。 单突变体杂交产生双突变体动物 已经证实这些激酶在某种程度上是功能冗余的。 为 例如，hck-/--src-/-双突变体发生严重的髓外 破骨细胞功能差和骨硬化症导致造血。 本项目的研究将侧重于持续表征 可获得单突变和双突变动物。 我们假设 在hck-/-巨噬细胞和hck-/-src-/-破骨细胞中观察到的缺陷可能导致 细胞粘附和整合素受体信号传导的损伤。 测试 这一点，以及为了便于分析突变细胞中的信号转导， 造血细胞系将衍生自突变小鼠。 研究 林恩激酶在B细胞和骨髓细胞中的作用，lyn-/-小鼠是 目前正在开发中。 我们假设林恩的缺陷 导致通过在嵌段中产生的表面μ =链的有缺陷的信号传导 B细胞发育和/或功能。 此外，我们将跨越 林恩=/=小鼠与hck=/=和src-/-突变体的比较，以寻找新的表型 在骨髓细胞中。 为了研究Src家族激酶在 巨核细胞生成，我们建议产生缺乏Matk/Hyl的小鼠。 激酶，作为Src家族成员的负调节因子， 巨核细胞和血小板。 我们假设这些动物会表现出 信号失调导致巨核细胞发育阻滞， 血小板形成或血小板功能。 这些研究的目的是 使用遗传学来定义这些信号通路， 激酶发挥生理上重要的功能。 最终这 这种方法将导致对酪氨酸作用的分子理解， 激酶在调节造血细胞生长、分化和 功能 这些研究将与Dr. DeFranco和Leavitt在输血医学的SCOR中。

Cytoplasmic tyrosine kinases play critical roles in intracellular signaling in hematopoietic cells. To study the functions of these kinases in blood cells we have used gene targeting in embryonic stem cells to generate mice with mutations in several sec family genes. We have concentrated on the hck, fgr, lyn, and src genes, the kinases encoded by these genes have been implicated in signaling pathways elicited by cytokines, lipopolysaccharide, and crosslinking of IgM and Fc receptors. Analysis of monocytes and macrophages from hck-/- mice has revealed a reduced ability to phagocytose latex heads. However, no other myeloid cell phenotypes have been found suggesting that the deficiency of Hck is complemented by other Src family kinases. Interbreeding of single mutants to generate double mutant animals has confirmed that these kinases are, in part, functionally redundant. For example, hck-/--src-/- double mutants develop severe extramedullary hematopoiesis as a result of poor osteoclast function and osteopetrosis. Research in this project will focus on a continued characterization of the available single and double mutant animals. We hypothesize that the defects seen in hck-/-macrophages and hck-/-src-/- osteoclasts may result from impairments in cell adhesion and integrin receptor signaling. To test this, and to facilitate analysis of signal transduction in mutant cells, hematopoietic cell lines will be derived forma the mutant mice. To study the role of the Lyn kinase in B-cells and myeloid cells, lyn-/- mice are currently being developed. We hypothesize that a deficiency in Lyn will result in defective signaling though surface mu=chains producing in a block in B-cell development and/or function. Additionally, we will cross the lyn=/= mice to the hck=/= and src-/- mutants to look for novel phenotypes in myeloid cells. In order to study the role of Src-family kinases in megakaryocytopoiesis, we propose to generate mice lacking the Matk/Hyl kinase, which serves as a negative regulator of Src-family members in megakaryocytes and platelets. We postulate that such animals will manifest dysregulated signaling causing blocks in megakaryocyte development, platelet formation or platelet function. The goal of these studies is to use genetics in order to define the signaling pathways in which these kinases play physiologically significant functions. Ultimately, this approach will lead to a molecular understanding of the roles of tyrosine kinases in the regulation of hematopoietic cell growth, differentiation and function. These studies will be carried out in collaboration with Drs. DeFranco and Leavitt within the SCOR in Transfusion medicine.