Differential expression of the two distinct replication protein A subunits from Cryptosporidium parvum
Differential expression of the two distinct replication protein A subunits from Cryptosporidium parvum
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DOI：
10.1002/jcb.21784
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发表时间：
2008-08-15
影响因子：
4
通讯作者：
Zhu, Guan
中科院分区：
文献类型：
--
作者：
Rider, Stanley Dean, Jr.;Zhu, Guan
顶复门寄生虫与其宿主不同，具有至少两种不同类型（长和短）的复制蛋白 A 大亚基 (RPAI)。早期的生化研究已经暗示了长型和短型 RPA1 蛋白的不同作用，但某些细节仍有待阐明。在本研究中，我们发现小隐孢子虫短型RPA1（CpRPA1A）在寄生虫的生殖早期阶段（该组寄生虫特有的细胞增殖过程）的S期高度表达，但在其他细胞周期阶段以低得多的水平存在于细胞质中。这一观察结果表明 CpRPA1A 可能负责寄生虫的一般 DNA 复制。另一方面，长型CpRPA1B蛋白在生命周期早期阶段的水平要低得多，但在参与性发育的后期阶段则升高，表明CpRPA1B可能在DNA重组中发挥作用。此外，CpRPA1B 可能会因紫外线照射而上调，表明这种长型 RPA1 可能参与 DNA 修复。总的来说，我们的数据表明，小隐孢子虫中的两种 RPA1 蛋白在这种寄生虫的 DNA 复制、修复和重组过程中发挥着不同的作用。
Apicomplexan parasites differ from their host by possessing at least two distinct types (long and short) of replication protein A large subunits (RPAI). Different roles for the long and short types of RPA1 proteins have been implied in early biochemical studies, but certain details remained to be elucidated. In the present study, we have found that the Cryptosporidium parvum short-typeRPA1 (CpRPA1A) was highly expressed at S-phase in parasites during the early stage of merogony (a cell multiplication process unique to this group of parasites), but otherwise present in the cytosol at a much lower level in other cell-cycle stages. This observation indicates that CpRPA1A is probably responsible for the general DNA replication of the parasite. On the other hand, the long-type CpRPA1B protein was present in a much lower level in the early life cycle stages, but elevated at later stages involved in sexual development, indicating that CpRPA1B may play a role in DNA recombination. Additionally, CpRPA1B Could be up-regulated by UV exposure, indicating that this long-type RPA1 is probably involved in DNA repair. Collectively, our data implies that the two RPA1 proteins in C. parvum are performing different roles during DNA replication, repair and recombination in this parasite.