scholarly journals Genomewide Screening Reveals High Levels of Insertional Polymorphism in the Human Endogenous Retrovirus Family HERV-K(HML2): Implications for Present-Day Activity

2005 ◽  
Vol 79 (19) ◽  
pp. 12507-12514 ◽  
Author(s):  
Robert Belshaw ◽  
Anna L. A. Dawson ◽  
John Woolven-Allen ◽  
Joanna Redding ◽  
Austin Burt ◽  
...  

ABSTRACT The published human genome sequence contains many thousands of endogenous retroviruses (HERVs) but all are defective, containing nonsense mutations or major deletions. Only the HERV-K(HML2) family has been active since the divergence of humans and chimpanzees; it contains many members that are human specific, as well as several that are insertionally polymorphic (an inserted element present only in some human individuals). Here we perform a genomewide survey of insertional polymorphism levels in this family by using the published human genome sequence and a diverse sample of 19 humans. We find that there are 113 human-specific HERV-K(HML2) elements in the human genome sequence, 8 of which are insertionally polymorphic (11 if we extrapolate to those within regions of the genome that were not suitable for amplification). The average rate of accumulation since the divergence with chimpanzees is thus approximately 3.8 × 10−4 per haploid genome per generation. Furthermore, we find that the number of polymorphic elements is not significantly different from that predicted by a standard population genetic model that assumes constant activity of the family until the present. This suggests to us that the HERV-K(HML2) family may be active in present-day humans. Active (replication-competent) elements are likely to have inserted very recently and to be present at low allele frequencies, and they may be causing disease in the individuals carrying them. This view of the family from a population perspective rather than a genome perspective will inform the current debate about a possible role of HERV-K(HML2) in human disease.

2000 ◽  
Vol 74 (8) ◽  
pp. 3715-3730 ◽  
Author(s):  
Michael Tristem

ABSTRACT Human endogenous retroviruses (HERVs) were first identified almost 20 years ago, and since then numerous families have been described. It has, however, been difficult to obtain a good estimate of both the total number of independently derived families and their relationship to each other as well as to other members of the familyRetroviridae. In this study, I used sequence data derived from over 150 novel HERVs, obtained from the Human Genome Mapping Project database, and a variety of recently identified nonhuman retroviruses to classify the HERVs into 22 independently acquired families. Of these, 17 families were loosely assigned to the class I HERVs, 3 to the class II HERVs and 2 to the class III HERVs. Many of these families have been identified previously, but six are described here for the first time and another four, for which only partial sequence information was previously available, were further characterized. Members of each of the 10 families are defective, and calculation of their integration dates suggested that most of them are likely to have been present within the human lineage since it diverged from the Old World monkeys more than 25 million years ago.


1998 ◽  
Vol 8 (11) ◽  
pp. 1097-1108 ◽  
Author(s):  
The Sanger Centre ◽  
The Washington University Genome Sequencing Cente

2018 ◽  
Author(s):  
Audrey T. Lin ◽  
Cindy G. Santander ◽  
Fabricia F. Nascimento ◽  
Emanuele Marchi ◽  
Timokratis Karamitros ◽  
...  

AbstractEndogenous retroviruses (ERVs) are remnants of ancient retroviral infections that make up 8% of the human genome. Although these elements are mostly fragmented and inactive, many proviruses belonging to the HERV-K (HML-2) family, the youngest lineage in the human genome, have intact open reading frames, some encoding for accessory genes called np9 and rec that interact with oncogenic pathways. Many studies have established that ERVs are transiently expressed in both stem cells and cancer, resulting in aberrant self-renewal and uncontrolled proliferation. np9 and rec expression are significantly correlated with a range of cancer stem cell (CSC) and epithelial to mesenchymal transition (EMT) biomarkers, including cellular receptors, transcription factors, and histone modifiers. Surprisingly, these ERV genes are negatively correlated with genes known to promote pluripotency in embryonic stem cell lines, such as Oct4. These results indicate that HERV-K (HML-2) is part of the transcriptional landscape responsible for cancer cells undergoing the phenotypic switch that characterises EMT. The discovery of np9 and rec’s correlation with CSC and EMT biomarkers suggest a yet undescribed role affecting the transitional CSC-like state in EMT and the shift towards cancer malignancy.ImportanceIn this study, we find that human endogenous retrovirus HERV-K (HML-2)-encoded genes np9 and rec are correlated with the expression of many biomarkers associated with cancer stem cells (CSC) and epithelial-mesenchymal transition (EMT). There has been a significant effort to develop novel treatments targeting CSC and EMT-specific signalling pathways and cell surface markers. This research describes HERV-K (HML-2) as interacting or being part of the regulatory network that make up reversible cell state switching in EMT. Our findings suggest these specific HERVs may be good candidate biomarkers in identifying the transitional CSC-like states that are present during the progression of EMT and cancer metastasis.


2011 ◽  
Vol 17 (2) ◽  
pp. 155-155
Author(s):  
Ewen Kirkness

2001 ◽  
Vol 1 ◽  
pp. 33-33

The human genome dominated science news last week. Both Science and Nature lead this week with articles about the simultaneous publication of the human genome sequence by the private company Celera Genomics and the publicly funded Human Genome Project (HGP).


Sign in / Sign up

Export Citation Format

Share Document