CDK5（Cyclin-Dependent Kinase 5）是丝氨酸/苏氨酸激酶，属细胞周期依赖激酶（CDK）家族成员，但与其他成员的功能不同，在细胞周期中不起作用。现已发现CDK5多个组织中表达，参与细胞粘附、迁移和分化。我们前期的研究发现CDK5在羊驼毛囊黑色素分布密集的毛乳头上方和外根鞘表达，在不同毛色的羊驼皮肤中CDK5的基因表达和蛋白表达均存在显著差异，且CDK5在体外培养的黑色素细胞中过表达会使毛色基因MC1R和TYR的表达量上升。该结果提示CDK5可能对黑色素细胞产生黑色素有调节作用。本项目主要采用脂质体转染法将CDK5基因及其shRNA转染羊驼黑色素细胞，检测转染后二者对GPCR路径上重要毛色基因的表达影响，以进行功能获得性和缺失性研究。该研究将揭示CDK5的新功能,即在黑色素细胞产生黑色素过程中起重要调控作用，为人为改造哺乳动物毛色提供理论依据和遗传资源。

The proline-directed serine/threonine kinase cyclin-dependent kinase 5 (CDK5) is a member of Cdk family of serine/threonine kinases. But CDK5 is different from the other members and does not regulate the cell cycle. Now it has been verified that CDK5 is expressed in many tissues, where it plays roles in cell adhesion, migration and differentiation.Our previous research found that CDK5 was expressed in the outer root sheath and upper hair bulb of alpaca skin where melanocytes are localized. CDK5 was differentially expressed between white and brown coat color. Moreover, over-expression of CDK5 in the alpaca melanocytes led to a significant increase of TYR and MC1R mRNA and protein, two molecules that have well established function in the skin color. Those results suggested that CDK5 may regulate melanogenesis in alpaca melanocytes. To investigate whether CDK5 also plays a role in regulating melanogenesis in alpaca, Liposome transfection method will be used to make melanocyte transfected by CDK5 over-expression and shRNA down-expression, and then the expression of MC1R and TYR will be tested. The result of gain-of-function and loss-of-function will give evidence of the function that CDK5 has a novel function in regulating the melanogenisis in alpaca.