Chromosomal assignment of human endogenous retrovirus K (HERV-K) <i>env open</i> reading frames

Abstract

The haploid human genome contains at least one human endogenous retrovirus K (HERV-K) env gene displaying an open reading frame, as evidenced by the high antibody titers against HERV-K Env in germ cell tumor patients at the time of tumor detection. However, the chromosomal assignment of an intact HERV-K env sequence is complicated by the existence of 25–30 HERV-K copies per haploid human genome. Recently, we reported the application of the protein truncation test (PTT) to chromosomally assign HERV-K gag open reading frames. Here, we set out to determine the chromosomal distribution of full-length HERV-K env genes. As demonstrated by somatic hybrid mapping and the PTT, HERV-K env open reading frames were found on human chromosomes 7, 19, and Y. By sequencing chromosome-specific HERV-K env subregions, we assigned two recently reported intact HERV-K sequences on human chromosomes 7 and 19, respectively. Chromosomes 7 and 19 and the Y are furthermore candidates for harboring a putative completely intact HERV-K locus.

Expression of the Human Endogenous Retrovirus (HERV) Group HML-2/HERV-K Does Not Depend on Canonical Promoter Elements but Is Regulated by Transcription Factors Sp1 and Sp3

“…Among the HERVs, the betaretrovirus subgroup HERV-K/ HML-2 (HERV-K), is unique in the respect that several proviruses have retained open reading frames for some, if not all, retroviral proteins and are still able to form retrovirus-like particles (7,36,44,45). HERV-K is a complex retrovirus carrying, inter alia, the rec gene, encoding a nuclear RNA export adapter essential for the expression of the viral proteins (37).…”

Identification of Human Endogenous Retrovirus-Specific T Cell Responses in Vertically HIV-1-Infected Subjects

“…Most HERV are defective due to the accumulation of mutations and deletions. However, some HERV families, e.g., HERV-H, HERV-W, HERV-K, and HERV-L, possess intact open reading frames encoding structural gene products (1,3,8,15,16) and are able to express these and other viral products under certain conditions (4,13). In addition, some HERV have been shown to be associated with some autoimmune diseases and cancers (20,21).…”

CpG Methylation Directly Regulates Transcriptional Activity of the Human Endogenous Retrovirus Family HERV-K(HML-2)

“…First, despite their long-time presence in the human genome, a number of proviruses still display open reading frames for retroviral Gag, Prt, Pol, and/or Env proteins (3,4,29,30,40). Second, transcriptional activity of the HERV-K(HML-2) family is strongly upregulated in human germ cell tumors (GCTs) and GCT-derived cell lines, as opposed to transcriptional silencing in non-GCT cell lines.…”