EXPRESSION AND BIOLOGICAL FUNCTION OF HUMAN ENDOGENOUS RETROVIRAL SEQUENCES (MEETING ABSTRACT)

Important note: Information in this article was accurate in 1992. The state of the art may have changed since the publication date.

EXPRESSION AND BIOLOGICAL FUNCTION OF HUMAN ENDOGENOUS RETROVIRAL SEQUENCES (MEETING ABSTRACT)

Fifteenth Symposium of the International Association for Comparative Research on Leukemia and Related Disease. October 6-11, 1991, Padova/Venice, Italy, p. 48, 1991.. Unique Identifier : AIDSLINE ICDB/92682399
Leib-Mosch C; Bachmann M; Brack-Werver R; Werner T; Erfle V; Hehlmann R; III Medizinische Klinik Mannheim der Universitat Heidelberg,; Wiesbadener Str. 7-11, D-6800 Mannheim 31, Germany

Abstract: The human genome contains a variety of retroviral elements resembling mammalian leukemia viruses. Most of these sequences have been found to be related to primate and murine C-type viruses (BaEV, SSAV/GaLV, MuLV), to murine B-type viruses and A-type particles (MMTV, IAP), or to human T-cell lymphotropic viruses (HTLV). Altogether, human endogenous retroviruses and retroviral elements are estimated to comprise at least 0.1 to 0.6% of the human genome. Some of these sequences have been shown to be transcriptionally active, especially in human placenta and fetal tissue and in human tumor cell lines. We have previously shown the human genome to contain a family of retroviral elements related to the simian sarcoma virus (SSV) and its associated virus, SSAV. One member of this family, S71, was analyzed in detail. Hybridization of human genomic DNA with specific S71 probes under low stringency conditions revealed that S71-related sequences comprise about 15-20 copies per human haploid genome. Furthermore, hybridization of various primate and rodent DNAs with S71 indicates that S71-related sequences entered the germline of primates between 18 and 40 million years ago. We have isolated various clones which hybridize specifically with S71 LTR from a human placenta cDNA library. The isolated clones seem to represent overlapping sequences of a single mRNA transcript. One LTR-related clone (P/124) was sequenced and compared to S71. The 3' end of P/124 contains an LTR-like sequence with sequence homology to S71 LTR. The U3 region of this LTR-like sequence shows elements resembling signals for transcriptional control. The remaining part of P/124 is not homologous to S71 or any known sequence and is obviously of nonretroviral origin. Elucidation of the biologic function of human endogenous retroviral elements has become increasingly important. Like other transposable elements, they contributed in shaping the eukaryotic genome by intracellular transposition events or by generating hot spots of recombination. Some human endogenous retroviral elements that are coexpressed with cellular sequences are supposed to play a role in the regulation of gene expression. Recently, some evidence has been found that endogenous retroviral elements may be involved in modulation of immunological functions. Furthermore, they may have a protective function against superinfection by related exogenous retroviruses. On the other hand, endogenous retroviruses and retroviral elements represent a reservoir of possibly pathogenic retroviral genes. They may be involved in chromosome aberration by recombination of related elements on different chromosomes. Furthermore, they can act as insertion mutagens and activate or inactivate cellular genes. Retroviral gene products themselves may also be pathogenic as has been shown for the immunosuppressive effects of P15E envelope proteins. Therefore, the role of human endogenous retroviruses and retroviral sequences in biological processes is currently a subject of great interest.

Keywords: Amino Acid Sequence Chromosome Aberrations DNA Insertion Elements DNA Probes DNA, Viral/GENETICS Gene Expression Regulation *Genome, Viral Nucleic Acid Hybridization Repetitive Sequences, Nucleic Acid/GENETICS Retroviridae/*GENETICS Sarcoma Viruses, Simian/*GENETICS Transcription, Genetic ABSTRACT
920830
M9281104

AEGiS is a 501(c)3, not-for-profit, tax-exempt, educational corporation. AEGiS is made possible through unrestricted funding from Boehringer Ingelheim, Bridgestone/Firestone Charitable Trust, Bristol-Myers Squibb Company, Elton John AIDS Foundation, Gill Foundation, the National Library of Medicine, Quest Diagnostics, Roche and Trimeris, and donations from users like you. Always watch for outdated information. This article first appeared in 1992. This material is designed to support, not replace, the relationship that exists between you and your doctor.

AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.

Copyright ©1980, 1992. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content. .