KAPOSIS SARCOMA ASSOCIATED HERPESVIRUS ENCODES FUNCTIONAL CYCLIN

卡波西肉瘤相关疱疹病毒含有一种病毒编码的 细胞周期蛋白（v-cyclin）。 KSHV v-细胞周期蛋白确实作为一种调节因子发挥作用， 细胞周期蛋白依赖性激酶6的亚基。 卡波西 肉瘤相关疱疹病毒（KSHV）（也称为人类疱疹病毒 8)在卡波西肉瘤病变和 体腔淋巴瘤 获得了一个17-kb的KSHV λ克隆 卡波西氏肉瘤病变组织 的DNA序列分析 该克隆鉴定了具有32%氨基酸残基的开放性切割框架， 同一性和53%的相似性病毒编码的细胞周期蛋白（v-细胞周期蛋白）的 与人疱疹病毒的同源性为31%，相似性为53 细胞周期蛋白D2。 该KSHV开放阅读框架显示编码 一种具有v-细胞周期蛋白特性的29- 30-kDa蛋白质。 KSHV 发现V-细胞周期蛋白主要与CDK 6相关， 细胞周期蛋白依赖性激酶，已知与细胞类型 D细胞周期蛋白和HVS v-细胞周期蛋白。 还发现KSHV v-细胞周期蛋白 与CDK 4弱结合。 KSHV v-cyclin-cdk 6复合物 磷酸化谷胱甘肽S-转移酶-Rb融合蛋白和组蛋白 H1作为体外底物。 因此，KSHV v-cyclin类似于v-cyclin， T淋巴细胞转化HVS的特异性， 与CDK 6的结合及其强烈激活CDK 6的能力 蛋白激酶活性

Kaposi's sarcoma-associated herpesvirus contains a virus-encoded cyclin (v-cyclin). KSHV v-cyclin indeed functions as a regulatory subunit of a cellular cyclin-dependent kinase 6. Kaposi's sarcoma-associated herpesvirus (KSHV) (also called human herpesvirus 8) is consistently found in Kaposi's sarcoma lesions and in body-cavity-based lymphomas. A 17-kb KSHV lambda clone was obtained directly from a Kaposi's sarcoma lesion. DNA sequence analysis of this clone identified an open rending frame which has 32% amino acid identity and 53% similarity to the virus-encoded cyclin (v-cyclin) of herpesvirus saimiri (HVS) and 31% identity and 53% similarity to human cellular cyclin D2. This KSHV open reading frame was shown to encode a 29- to 30-kDa protein with the properties of a v-cyclin. KSHV v-cyclin protein was found to associate predominantly with cdk6, a cellular cyclin-dependent kinase known to interact with cellular type D cyclins and HVS v-cyclin. The KSHV v-cyclin was also found to associate weakly with cdk4. KSHV v-cyclin-cdk6 complexes strongly phosphorylated glutathione S-transferase-Rb fusion protein and histone H1 as substrates in vitro. Thus, KSHV v-cyclin resembles the v-cyclin of the T-lymphocyte-transforming HVS in its specificity for association with cdk6 and in its ability to strongly activate cdk6 protein kinase activity.