HERV-F(XA34) is a full-length human endogenous retrovirus expressed in placental and fetal tissues

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• 作者：Kjellman ; Christian ; Sjö ; gren ; Hans-Olov ; Salford ; Leif G. ; Widegren ; Bengt
• 关键词：Adseverin(D5) ; EST ; Gag ; Genomic sequence ; Splicing ; WUGSC ; H_DJ0722F20.1 ; bp ; base pair(s) ; Env ; envelope ; Gag ; group-specific antigen ; HERV ; human endogenous retrovirus ; IN ; integrase ; kb ; kilobase pair(s) ; LTR ; long terminal repeat ; PBS ; primer binding
• 刊名：Gene
• 出版年：1999
• 出版时间：October 18, 1999
• 年：1999
• 卷：239
• 期：1
• 页码：99-107
• 全文大小：441 K

文摘

The complete sequence of XA34 was identified from a 107kb genomic clone originating from the human chromosome 7q31.1-q31.3. The 7.1kb human endogenous retrovirus (HERV) contains LTR's, gag, pol and env, and a pol sequence which is identical to the 2.3kb XA34 cDNA clone which we previously isolated from a human glioma cDNA library (). The HERV is located in a reversed orientation within an intron-sequence of a gene similar to mouse adseverin(D5). The gag and protease regions are intact. However, the pol and env regions are truncated by a deletion which removes the C-terminal end of the integrase and the complete surface protein. The HERV sequence is bordered by a five base-pair direct repeat and has the TG…CA structure. Over the complete HERV genome, XA34 is very similar to members of the HERV-F family and shares the same primer binding site which is homologous to phenylalanine (F) tRNA. Therefore, XA34 is termed HERV-F(XA34). HERV-F(XA34) has an open reading frame (ORF) of 1000bp in the gag region which starts with Met-Gly in a favorable context and stops in the capsid protein. A strong mRNA expression of HERV-F(XA34) is demonstrated in placental tissue, mainly residing in two transcripts of approximately 7.5 and 8.5–9kb respectively. Analyses of expressed sequence tags (ESTs) have identified the expression of HERV-F(XA34) sequences in placental tissue, fetal liver/spleen, olfactory epithelium and in an epithelial skin tumor. EST analysis has also identified splice variants of HERV-F(XA34), in which the gag, pol and most of the env regions are spliced out. These splice variants contain a short ORF encoded in the region from the C-terminal portion of env to the 3′-LTR. In addition, ESTs identical to HERV-Fb have been identified in retinal, fetal liver/spleen and brain tissue as well as Jurkat cells. The analyses indicate that the 5′-LTR of HERV-Fb may function as an alternative poly A site of a Krüppel related zinc finger gene (ZNF195).