Analysis of sinnalling pathway of apoptosis degradation using PKCδ gene-targeting mice

蛋白激酶Cδ (PKCδ)是PKC家族成员的一种亚型，在细胞凋亡时被半胱天冬酶裂解，从而转化为活化的PKCδ。本研究旨在通过培养PKCδ基因缺失小鼠来阐明PKCδ的生理功能。我们构建了靶向载体，并将其转染到胚胎干细胞中，获得了PKCδ位点的胚胎干细胞同源重组体。按照标准方法制备基因消融小鼠，用突变的ES细胞制备pkc δ缺陷小鼠。pkc δ缺陷小鼠存活，健康，不容易发生癌症。pkc δ缺陷小鼠的组织学检查显示T淋巴细胞和B淋巴细胞异常积聚导致脾肿大。在淋巴结中，B细胞数量的增加比T细胞的增加更明显。体外培养实验表明，pkc δ缺陷B细胞生长速度快于野生型B细胞。我们得出结论，由于缺乏发育异常，PKCδ对发育过程中的细胞凋亡不是必需的。此外，pkc δ缺陷小鼠胸腺细胞和胚胎成纤维细胞的凋亡似乎不受影响。然而，B细胞的凋亡程度似乎有所降低，这表明PKCδ可能在B细胞凋亡的信号通路中发挥重要作用。

It has been reported that protein kinase Cδ (PKCδ) a subtype of PKC family members, is cleaved by caspase resulting in conversion to activated PKCδ upon apoptosis. The aim of this research project is to elucidate the physiological function of PKCδ by generating mice deficient in PKCδ gene.We constructed the targeting vector and transfect it into embryonic stem (ES) cells to obtain the homologous recombinant of ES cells for PKCδ locus. According to the standard method to generate gene-ablated mice, PKCδ-deficient mice were produced with the mutant ES cells. The PKCδ-deficient mice were viable, healthy, and not prone to cancer development.Histlogical examinations of the PKCδ-deficient mice revealed splenomegaly due to abnormal accumulation of T and B lymphocytes. In lymph nodes, increase in the number of B cells was more apparent than that of T cells. In vitro culture experiments showed that PKCδ-deficient B cells grew faster than wild-type B cells.We concluded that PKCδ is not essential for the apoptosis during development, because of the lack of developmental abnormalities. Furthermore, apoptosis of thymovytes and embryonic fibroblasts from PKCδ-deficient mice seems unaffected. However, the extent of apoptosis in B cells appeared to be reduced, suggesting that PKCδ may play an important role in the signaling pathway of apoptosis in B cells.