牛泡沫病毒BFV3026细胞感染性的确立及包装细胞系的建立

分别将牛泡沫病毒BFV3026接种于胎牛肺细胞(FBL)、牛肺细胞系(BL12)、新生牛肾细胞(NBK)、兔肺细胞(RL)、人乳腺癌上皮细胞(MCF)、293T、HeLa、CV-1、CHO等9种细胞,通过对它们及其传代细胞的病变观察与RT-PCR检测,确立BFV3026对这9种细胞的感染。并以BFV3026原病毒DNA为模板,通过PCR构建以pcD NA3 1(-)为载体的gag-pol、env真核表达质粒共转染BL12细胞,经G418持续筛选,获得8个NeoR细胞克隆。RT-PCR及包装实验证实:其中7个细胞克隆能有效行使包装辅助功能。

牛泡沫病毒中国株感染兔的研究

将牛泡沫病毒(BFV3026)感染的细胞经耳缘静脉注射兔子,并以正常细胞注射的兔为对照。1年后处死,病毒挽救实验及PCR检测显示:兔经一次注射即可被BFV3026感染,病毒广泛分布于感染兔的多种脏器中,通过共培养可从感染兔血、肝、脾、肺、肾中拯救出相应感染性病毒颗粒,并在脑、骨髓、心、胰、肠系膜中检到高拷贝BFV原病毒DNA存在。同时,血清学检测表明:感染兔在接受注射一个月后即产生高滴度抗病毒蛋白抗体,并维持该滴度水平直至实验终止,兔未表现任何可观病变。

Borf-1 protein identified as a transcriptional trans-activator of bovine foamy virus

Bovine foamy virus (BFV), a member of the spumavirus subfamily of retroviruses,contains two open reading frames (ORF-1 and ORF-2) in addition to the genes coding for gag,po/and env. Borf-1 protein, encoded by BFV ORF-1, is identified as a transcriptional transactivator, which augments gene expression directed by the viral long terminal repeat (LTR).Further investigations in transient expression assays reveal that the Borf-1 responsive elements are located in the U3 domain of the LTR, upstream from position -140 ( + 1 represents the transcription initiation site), and the BFV RU5 region has an inhibitory effect in LTR-directed gene expression.