Sleeman J P, Laskey R A
Wellcome/CRC Institute, Cambridge, UK.
Oncogene. 1993 Jan;8(1):67-77.
v-ski is a virally transduced nuclear oncogene. The biology of its cellular progenitors is only poorly understood. The early development of Xenopus laevis provides an excellent model system for studying the role of genes in proliferation, differentiation and development. We have therefore characterized Xenopus c-ski. We report that Xenopus c-ski transcripts are maternally regulated during early development, and are widely expressed in adult tissues. Structural predictions indicate the presence of a previously unreported extensive C-terminal helical domain in Xenopus c-ski and ski-related proteins from other species. This domain shows homologies with proteins which contain heptad repeats characteristic of elongated coiled-coil formation, like myosin and the intermediate filament proteins, and itself has a heptad repeat structure. The ski C-terminal domain also contains two other previously unreported elements, a novel strictly alternating hydrophobic-basic motif that repeats along the helical domain, and an underlying 25-mer repeated sequence. The significance of these findings is discussed with reference to c-ski function and to the oncogenic activation of v-ski, which is a truncated version of c-ski and thus does not have the C-terminal helical domain.
v-ski是一种病毒转导的核致癌基因。对其细胞起源的生物学特性了解甚少。非洲爪蟾的早期发育为研究基因在增殖、分化和发育中的作用提供了一个极佳的模型系统。因此，我们对非洲爪蟾的c-ski进行了特性描述。我们报告称，非洲爪蟾c-ski转录本在早期发育过程中受母体调控，并在成体组织中广泛表达。结构预测表明，非洲爪蟾c-ski及其他物种的ski相关蛋白中存在一个此前未报道的广泛的C端螺旋结构域。该结构域与包含七肽重复序列（这是形成延长卷曲螺旋的特征）的蛋白质具有同源性，如肌球蛋白和中间丝蛋白，并且其自身具有七肽重复结构。ski C端结构域还包含另外两个此前未报道的元件，一个沿着螺旋结构域重复的新型严格交替的疏水-碱性基序，以及一个潜在的25聚体重复序列。结合c-ski的功能以及v-ski的致癌激活作用对这些发现的意义进行了讨论，v-ski是c-ski的截短版本，因此不具有C端螺旋结构域。
