The endogenous retroviral NP9 gene was isolated and cloned using reverse transcription polymerase chain reaction (RT-PCR) and T-A cloning techniques, and its sequence was determined with Perkin-Elmer ABI 377 DNA Sequencer.

• 对NPg基因编码的蛋白质序列分析结果显示:NPg表达的蛋白质是一种强碱性蛋白质，其等电点为9.；59，其中精氨酸占13