Coamplification and dispersion of adjacent human endogenous retroviral HERV-H and HERV-E elements; presence of spliced hybrid transcripts in normal leukocytes.
In an RT-PCR study of HERV-H spliced subgenomic transcripts, we found transcripts with HERV-H leader and protease-encoding sequences spliced to HERV-E integrase-encoding sequences in lymphocytes from healthy blood donors. In other cell types, including two T-cell leukemia cell lines, these transcripts were absent. The PCR fragments of the hybrid transcripts contained two open reading frames (ORFs). One was a hybrid HERV-H protease/HERV-E integrase ORF and the other was the HERV-E envelope surface glycoprotein ORF. Alternative splice products were also identified. The genomic DNA origin of the hybrid transcripts was shown to be a HERV-H element with a large 3'-end deletion, adjacent to a HERV-E element lacking the 5'-LTR. This hybrid structure was shown to be amplified and dispersed to six different human chromosomes. Thus, a relatively large part of full-length HERV-E elements (15-20%) is potentially under the transcriptional control of HERV-H LTRs. The HERV-H/HERV-E junction was present in multiple copies also in the chimpanzee and gorilla, but not in the orangutan or old world monkeys.
Lindeskog
M
M
Department of Medical Microbiology, Lund University, Sweden. mats.lindeskog@mmb.lu.se
Medstrand
P
P
Cunningham
A A
AA
Blomberg
J
J
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004279:DNA, Viral; D015894:Genome, Human; D006801:Humans; D007962:Leukocytes / Q000821:virology*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016133:Polymerase Chain Reaction; D011323:Primates / Q000821:virology; D012367:RNA, Viral / Q000737:chemistry; D012190:Retroviridae / Q000235:genetics*; D014407:Tumor Cells, Cultured
D004279:DNA, Viral; D012367:RNA, Viral