Skopp R, Wang W, Price C
Department of Chemistry, University of Nebraska, Lincoln, NE 68588, USA.
Chromosoma. 1996 Aug;105(2):82-91. doi: 10.1007/BF02509517.
In this paper we describe the isolation and characterization of rTP, the replication Telomere Protein, formerly known as the telomere protein homolog. The rTP was initially identified because of its homology to the gene for the Oxytricha telomere-binding protein alpha-subunit. The protein encoded by the rTP gene has extensive amino acid sequence identity to the DNA-binding domain of the telomere-binding proteins from both Euplotes crassus and Oxytricha nova. We have now identified the protein encoded by the rTP gene and have shown that it differs from the telomere-binding protein in its abundance, solubility and intracellular location. To learn more about the function of rTP, we determined when during the Euplotes life cycle the gene is transcribed. The transcript was detectable only in nonstarved vegetative cells and during the final stages of macronuclear development. Since the peak transcript level coincided with the rounds of replication that take place toward the end of macronuclear development, it appeared that rTP might be involved in DNA replication. Immunolocalization experiments provided support for this hypothesis as antibodies to rTP specifically stain the replication bands. Replication bands are the sites of DNA replication in Euplotes macronuclei. Our results suggest that rTP may be a new telomere replication factor.
在本文中，我们描述了复制端粒蛋白rTP（以前称为端粒蛋白同源物）的分离和特性。rTP最初是因其与嗜热四膜虫端粒结合蛋白α亚基基因的同源性而被鉴定出来的。rTP基因编码的蛋白质与粗壮真核游仆虫和新奥四膜虫的端粒结合蛋白的DNA结合结构域具有广泛的氨基酸序列同一性。我们现已鉴定出rTP基因编码的蛋白质，并表明它在丰度、溶解度和细胞内定位方面与端粒结合蛋白不同。为了更多地了解rTP的功能，我们确定了在真核游仆虫生命周期的何时该基因被转录。转录本仅在未饥饿的营养细胞和大核发育的最后阶段可检测到。由于转录本水平的峰值与大核发育末期发生的复制轮次一致，因此似乎rTP可能参与DNA复制。免疫定位实验为这一假设提供了支持，因为针对rTP的抗体特异性地标记了复制带。复制带是真核游仆虫大核中DNA复制的位点。我们的结果表明，rTP可能是一种新的端粒复制因子。
