SRC FAMILY PROTEIN TYROSINE KINASES IN HEMATOPOIESIS

胞质酪氨酸激酶在细胞内信号转导中起关键作用 在造血细胞中。研究这些蛋白在血液中的功能 我们已经在胚胎干细胞中使用基因打靶技术来产生小鼠 有几个SEC家族基因的突变。我们把注意力集中在 Hck、fgr、lyn和src基因，这些基因编码的激酶 与细胞因子、内毒素、 Ig M和Fc受体的交联性。单核细胞的分析和 HCK-/-小鼠的巨噬细胞吞噬能力降低 乳胶头。然而，尚未发现其他髓系细胞表型。 提示HCK基因的缺失与其他Src家族互补 激活剂。单突变体杂交产生双突变动物 已经证实，这些激酶在一定程度上是功能冗余的。为 例如，hkk-/-src-/-双突变体发展成严重的髓外 破骨细胞功能差和骨化症所致的造血功能障碍。 这个项目的研究将集中在对 可提供单突变和双突变动物。我们假设 可能导致HCK-/-巨噬细胞和HCK-/-src-/-破骨细胞出现缺陷 细胞黏附和整合素受体信号的损伤。为了测试 为了便于分析突变细胞中的信号转导， 突变的小鼠将获得造血细胞系。学习 Lyn-/-小鼠在B细胞和髓系细胞中的作用 目前正在开发中。我们假设林恩的缺陷将会 通过表面MU=在块中产生的链导致有缺陷的信令 在B细胞发育和/或功能方面。此外，我们将越过 Lyn=/=小鼠对hck=/=和src-/-突变体寻找新的表型 在髓系细胞中。为了研究Src家族蛋白在细胞周期调控中的作用 巨核细胞生成，我们建议产生缺乏Matk/hyl的小鼠 作为src家族成员的负性调节因子 巨核细胞和血小板。我们假设这样的动物将会出现 信号失控导致巨核细胞发育受阻， 血小板形成或血小板功能。这些研究的目标是 使用遗传学来定义在这些信号通路中 激酶在生理上起着重要的作用。归根结底，这 这种方法将导致对酪氨酸作用的分子理解 蛋白水解酶在造血细胞生长、分化和调控中的作用 功能。这些研究将与戴维斯博士合作进行。 DeFranco和Leavitt在输血医学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.