Shugart E C, Levenson A S, Constance C M, Umek R M
Department of Biology, University of Virginia, Charlottesville 22903, USA.
Cell Growth Differ. 1995 Dec;6(12):1541-7.
The characterization of growth arrest-associated genes has revealed that cells actively suppress mitotic growth in response to extracellular signals. Mouse 3T3-L1 cells growth arrest at multiple distinct points during terminal differentiation to adipocytes. We examined the expression of growth arrest-specific (gas) and growth arrest- and DNA damage-inducible (gadd) genes as a function of 3T3-L1 growth arrest and adipocyte development. These growth arrest-associated genes are differentially expressed throughout adipocyte development. Some of the gas/gadd genes are preferentially expressed in a subset of growth arrest states. In contrast, gas1 and gas3 are expressed in serum-starved adipoblasts, contact-inhibited adipoblasts, and post-mitotic adipocytes. However, in post-mitotic adipocytes, gas1 and gas3 are induced in response to nutrient deprivation, not altered growth status. gas6 is an exception to the general concordance of mitotic growth arrest and gas/gadd expression in that gas6 is preferentially expressed during the clonal expansion of postconfluent adipoblasts. Combined, the expression patterns indicate that growth arrest-associated genes are regulated by numerous signal transduction pathways throughout a discrete developmental transition.
对生长停滞相关基因的表征显示，细胞会响应细胞外信号而积极抑制有丝分裂生长。小鼠3T3-L1细胞在向脂肪细胞终末分化的多个不同阶段发生生长停滞。我们研究了生长停滞特异性（gas）基因和生长停滞及DNA损伤诱导（gadd）基因的表达，作为3T3-L1细胞生长停滞和脂肪细胞发育的函数。这些生长停滞相关基因在整个脂肪细胞发育过程中差异表达。一些gas/gadd基因在特定的生长停滞状态子集中优先表达。相比之下，gas1和gas3在血清饥饿的成脂细胞、接触抑制的成脂细胞和有丝分裂后的脂肪细胞中表达。然而，在有丝分裂后的脂肪细胞中，gas1和gas3是对营养剥夺作出反应而被诱导，而非生长状态改变。gas6是有丝分裂生长停滞与gas/gadd表达一般一致性的一个例外，因为gas6在汇合后成脂细胞的克隆扩增期间优先表达。综合来看，这些表达模式表明生长停滞相关基因在整个离散的发育转变过程中受到众多信号转导途径的调控。
