Proteolytic processing and assembly of gag and gag-pol proteins of TED, a baculovirus-associated retrotransposon of the gypsy family.
Proteolytic processing and assembly of gag and gag-pol proteins of TED, a baculovirus-associated retrotransposon of the gypsy family.
复制标题
TED 的 gag 和 gag-pol 蛋白的蛋白水解加工和组装，TED 是吉普赛家族的杆状病毒相关逆转录转座子。
DOI：
10.1128/jvi.72.11.8718-8724.1998
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发表时间：
1998
影响因子：
5.4
通讯作者：
Friesen,PD
中科院分区：
文献类型：
--
作者：
Hajek,KL;Friesen,PD
TED (transposable element D) is anenv-containing member of the gypsy family of retrotransposons that represents a possible retrovirus of invertebrates. This lepidopteran (moth) retroelement containsgagandpolgenes that encode proteins capable of forming viruslike particles (VLP) with reverse transcriptase. Since VLP are likely intermediates in TED transposition, we investigated the roles ofgagandpolin TED capsid assembly and maturation. By using constructed baculovirus vectors and TED Gag-specific antiserum, we show that the principal translation product ofgag(Pr55gag) is cleaved to produce a single VLP structural protein, p37gag. Replacement of Asp436within the retrovirus-like active site of thepol-encoded protease (PR) abolished Pr55gagcleavage and demonstrated the requirement for PR in capsid processing. As shown by expression of an in-frame fusion of TEDgagandpol, PR is derived from the Gag-Pol polyprotein Pr195gag-pol. The PR cleavage site within Pr55gagwas mapped to a position near the junction of a basic, nucleocapsid-like domain and a C-terminal acidic domain. Once released by cleavage, the C-terminal fragment was not detected. This acidic fragment was dispensable for VLP assembly, as demonstrated by the formation of VLP by C-terminal Pr55gagtruncation proteins and replacement of the acidic domain with a heterologous protein. In contrast, C-terminal deletions that extended into the adjacent nucleocapsid-like domain of Pr55gagabolished VLP recovery and demonstrated that this central region contributes to VLP assembly or stability, or both. Collectively, these data suggest that the single TED protein p37gagprovides both capsid and nucleocapsid functions. TED may therefore use a simple processing strategy for VLP assembly and genome packaging.
