Expression of extensin genes is dependent on the stage of the cell cycle and cell proliferation in suspension-cultured Catharanthus roseus cells
Expression of extensin genes is dependent on the stage of the cell cycle and cell proliferation in suspension-cultured Catharanthus roseus cells
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DOI：
10.1023/a:1005913818129
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发表时间：
1998-02-01
影响因子：
5.1
通讯作者：
Watanabe, A
中科院分区：
文献类型：
--
作者：
Ito, M;Kodama, H;Watanabe, A
为了分离在高等植物细胞周期的特定阶段表达的cDNA，我们对从同步培养的长春花S期细胞制备的cDNA文库进行了差异筛选。序列分析表明，两个确定的cDNA，cyc 15和cyc 17，编码的伸展蛋白，代表一个家庭的细胞壁羟脯氨酸丰富的糖蛋白。从这两个cDNA推导的蛋白质序列含有特征性的五肽重复序列，Ser-Pro-Pro-Pro-Pro，这在伸展蛋白中常见。这些蛋白质序列还具有几个其他伸展蛋白特征，例如存在N-末端信号肽和高含量的Tyr和Lys残基。当C.用磷酸盐饥饿法使悬浮培养的roseus细胞同步化，cyc 15和cyc 17的mRNA在细胞周期的S期和G2期瞬时表达。然而，大量的mRNA也积累在磷酸盐饥饿的细胞停滞在G1期。在异步培养中，这两个基因在静止期，当细胞增殖停止时表达。观察到的表达模式表明，伸展蛋白基因，cyc 15和cyc 17，是在两种类型的调节：一个依赖于细胞周期的阶段，另一个是在生长停滞过程中诱导。因此，这些基因的产物可以在细胞周期的进展过程中和细胞分裂后细胞壁的强化中发挥作用。
To isolate cDNAs expressed at a specific phase of the cell cycle in a higher plant, we performed differential screening of a cDNA library prepared from the S-phase cells of synchronized cultures of Catharanthus roseus. Sequence analysis shows that two of the identified cDNAs, cyc15 and cyc17, encode extensins that represent a family of cell wall hydroxyproline-rich glycoproteins. Protein sequences deduced from the two cDNAs contain the characteristic pentapeptide repeat sequence, Ser-Pro-Pro-Pro-Pro, which is commonly observed in extensins. The protein sequences also share several other extensin characteristics such as the presence of a N-terminal signal peptide and a high content of Tyr and Lys residues. When C. roseus cell suspension cultures were synchronized by phosphate starvation, the mRNAs of both cyc15 and cyc17 were transiently expressed during the S and G2 phases of the cell cycle. However, significant amounts of the mRNAs also accumulated in phosphate-starved cells arrested in the G1 phase. In asynchronous cultures, both genes were expressed during the stationary phase, when cell proliferation ceased. The observed patterns of expression suggest that the extensin genes, cyc15 and cyc17, are under two types of regulation: one that depends on the stage of the cell cycle and another that is induced during the growth arrest. Thus, the products of these genes may function both during the progression through the cell cycle and in the strengthening of the cell wall after cell division.