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Modulation of human endogenous retrovirus (HERV) transcription during persistent and de novo HIV-1 infection.

Vincendeau M, Göttesdorfer I, Schreml JM, Wetie AG, Mayer J, Greenwood AD, Helfer M, Kramer S, Seifarth W, Hadian K, Brack-Werner R, Leib-Mösch C - Retrovirology (2015)

Bottom Line: Analysis of transcripts from individual members of this group revealed up-regulation of predominantly two proviral loci (ERVK-7 and ERVK-15) on chromosomes 1q22 and 7q34 in persistently infected KE37.1 cells, as well as in de novo HIV-1 infected LC5 cells, while only one single HML-2 locus (ERV-K6) on chromosome 7p22.1 was activated in persistently infected LC5 cells.Our results demonstrate that HIV-1 can alter HERV transcription patterns of infected cells and indicate a correlation between activation of HERV elements and the level of HIV-1 production.Moreover, our results suggest that the effects of HIV-1 on HERV activity may be far more extensive and complex than anticipated from initial studies with clinical material.

View Article: PubMed Central - PubMed

Affiliation: Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany. michelle.vincendeau@helmholtz-muenchen.de.

ABSTRACT

Background: The human genome contains multiple LTR elements including human endogenous retroviruses (HERVs) that together account for approximately 8-9% of the genomic DNA. At least 40 different HERV groups have been assigned to three major HERV classes on the basis of their homologies to exogenous retroviruses. Although most HERVs are silenced by a variety of genetic and epigenetic mechanisms, they may be reactivated by environmental stimuli such as exogenous viruses and thus may contribute to pathogenic conditions. The objective of this study was to perform an in-depth analysis of the influence of HIV-1 infection on HERV activity in different cell types.

Results: A retrovirus-specific microarray that covers major HERV groups from all three classes was used to analyze HERV transcription patterns in three persistently HIV-1 infected cell lines of different cellular origins and in their uninfected counterparts. All three persistently infected cell lines showed increased transcription of multiple class I and II HERV groups. Up-regulated transcription of five HERV taxa (HERV-E, HERV-T, HERV-K (HML-10) and two ERV9 subgroups) was confirmed by quantitative reverse transcriptase PCR analysis and could be reversed by knock-down of HIV-1 expression with HIV-1-specific siRNAs. Cells infected de novo by HIV-1 showed stronger transcriptional up-regulation of the HERV-K (HML-2) group than persistently infected cells of the same origin. Analysis of transcripts from individual members of this group revealed up-regulation of predominantly two proviral loci (ERVK-7 and ERVK-15) on chromosomes 1q22 and 7q34 in persistently infected KE37.1 cells, as well as in de novo HIV-1 infected LC5 cells, while only one single HML-2 locus (ERV-K6) on chromosome 7p22.1 was activated in persistently infected LC5 cells.

Conclusions: Our results demonstrate that HIV-1 can alter HERV transcription patterns of infected cells and indicate a correlation between activation of HERV elements and the level of HIV-1 production. Moreover, our results suggest that the effects of HIV-1 on HERV activity may be far more extensive and complex than anticipated from initial studies with clinical material.

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Relative transcriptional activity of selected HERV subgroups. Relative transcript levels of (A) HERV taxa S71pCRTK-1 (group HERV-T), (B) E4-1 (group HERV-E), (C) ERV9 and Seq59 (both group ERV9) and (D) HERV-KC4 (group HERV-K (HML-10)) were determined by qRT-PCR. The Y-axis shows the x-fold relative expression of HERV-transcripts in infected cells referred to uninfected cells. Relative transcription was quantified according to [85] and normalized to RNA Polymerase II (RPII) transcript levels. Standard errors for triplicate experiments are indicated.
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Fig3: Relative transcriptional activity of selected HERV subgroups. Relative transcript levels of (A) HERV taxa S71pCRTK-1 (group HERV-T), (B) E4-1 (group HERV-E), (C) ERV9 and Seq59 (both group ERV9) and (D) HERV-KC4 (group HERV-K (HML-10)) were determined by qRT-PCR. The Y-axis shows the x-fold relative expression of HERV-transcripts in infected cells referred to uninfected cells. Relative transcription was quantified according to [85] and normalized to RNA Polymerase II (RPII) transcript levels. Standard errors for triplicate experiments are indicated.

Mentions: Differences in the transcription levels of five representative HERV subgroups in infected and non-infected cells were subsequently analyzed by qRT-PCR using primers that bind specifically to the pol region of the up-regulated HERVs. These primers are located in a region of the reverse transcriptase gene that exhibits only marginal similarity among HERV-taxa with one primer matching the sequence of the corresponding microarray capture probes [46,48]. Figure 3 shows the relative transcript levels of the selected HERV taxa S71pCRTK-1 (group HERV-T), E4-1 (group HERV-E), ERV9 and Seq59 (both group ERV9), and HERV-KC4 (group HML-10) in the HIV-1 infected cells compared to the uninfected control cells. Transcript levels of HERV subgroups S71pCRTK-1 (Figure 3A) and Seq59 (Figure 3C) were only slightly increased, whereas levels of E4-1 (Figure 3B), ERV9 (Figure 3C) and HERV-KC4 (Figure 3D) were up to 15fold higher in HIV-1 infected cells than in uninfected cells. This result was in agreement with the microarray data (Figure 2A). The cell lines with high HIV-1 production (KE37.1-IIIB and LC5-HIV) demonstrated higher HERV transcription than the non-productive TH4-7-5 cells. Thus, the results obtained by two independent methods indicate that persistent HIV-1 infection increases transcription of at least one member of each of 5 HERV subgroups and that transcription levels of these HERVs are related to HIV-1 production.Figure 3


Modulation of human endogenous retrovirus (HERV) transcription during persistent and de novo HIV-1 infection.

Vincendeau M, Göttesdorfer I, Schreml JM, Wetie AG, Mayer J, Greenwood AD, Helfer M, Kramer S, Seifarth W, Hadian K, Brack-Werner R, Leib-Mösch C - Retrovirology (2015)

Relative transcriptional activity of selected HERV subgroups. Relative transcript levels of (A) HERV taxa S71pCRTK-1 (group HERV-T), (B) E4-1 (group HERV-E), (C) ERV9 and Seq59 (both group ERV9) and (D) HERV-KC4 (group HERV-K (HML-10)) were determined by qRT-PCR. The Y-axis shows the x-fold relative expression of HERV-transcripts in infected cells referred to uninfected cells. Relative transcription was quantified according to [85] and normalized to RNA Polymerase II (RPII) transcript levels. Standard errors for triplicate experiments are indicated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4375885&req=5

Fig3: Relative transcriptional activity of selected HERV subgroups. Relative transcript levels of (A) HERV taxa S71pCRTK-1 (group HERV-T), (B) E4-1 (group HERV-E), (C) ERV9 and Seq59 (both group ERV9) and (D) HERV-KC4 (group HERV-K (HML-10)) were determined by qRT-PCR. The Y-axis shows the x-fold relative expression of HERV-transcripts in infected cells referred to uninfected cells. Relative transcription was quantified according to [85] and normalized to RNA Polymerase II (RPII) transcript levels. Standard errors for triplicate experiments are indicated.
Mentions: Differences in the transcription levels of five representative HERV subgroups in infected and non-infected cells were subsequently analyzed by qRT-PCR using primers that bind specifically to the pol region of the up-regulated HERVs. These primers are located in a region of the reverse transcriptase gene that exhibits only marginal similarity among HERV-taxa with one primer matching the sequence of the corresponding microarray capture probes [46,48]. Figure 3 shows the relative transcript levels of the selected HERV taxa S71pCRTK-1 (group HERV-T), E4-1 (group HERV-E), ERV9 and Seq59 (both group ERV9), and HERV-KC4 (group HML-10) in the HIV-1 infected cells compared to the uninfected control cells. Transcript levels of HERV subgroups S71pCRTK-1 (Figure 3A) and Seq59 (Figure 3C) were only slightly increased, whereas levels of E4-1 (Figure 3B), ERV9 (Figure 3C) and HERV-KC4 (Figure 3D) were up to 15fold higher in HIV-1 infected cells than in uninfected cells. This result was in agreement with the microarray data (Figure 2A). The cell lines with high HIV-1 production (KE37.1-IIIB and LC5-HIV) demonstrated higher HERV transcription than the non-productive TH4-7-5 cells. Thus, the results obtained by two independent methods indicate that persistent HIV-1 infection increases transcription of at least one member of each of 5 HERV subgroups and that transcription levels of these HERVs are related to HIV-1 production.Figure 3

Bottom Line: Analysis of transcripts from individual members of this group revealed up-regulation of predominantly two proviral loci (ERVK-7 and ERVK-15) on chromosomes 1q22 and 7q34 in persistently infected KE37.1 cells, as well as in de novo HIV-1 infected LC5 cells, while only one single HML-2 locus (ERV-K6) on chromosome 7p22.1 was activated in persistently infected LC5 cells.Our results demonstrate that HIV-1 can alter HERV transcription patterns of infected cells and indicate a correlation between activation of HERV elements and the level of HIV-1 production.Moreover, our results suggest that the effects of HIV-1 on HERV activity may be far more extensive and complex than anticipated from initial studies with clinical material.

View Article: PubMed Central - PubMed

Affiliation: Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany. michelle.vincendeau@helmholtz-muenchen.de.

ABSTRACT

Background: The human genome contains multiple LTR elements including human endogenous retroviruses (HERVs) that together account for approximately 8-9% of the genomic DNA. At least 40 different HERV groups have been assigned to three major HERV classes on the basis of their homologies to exogenous retroviruses. Although most HERVs are silenced by a variety of genetic and epigenetic mechanisms, they may be reactivated by environmental stimuli such as exogenous viruses and thus may contribute to pathogenic conditions. The objective of this study was to perform an in-depth analysis of the influence of HIV-1 infection on HERV activity in different cell types.

Results: A retrovirus-specific microarray that covers major HERV groups from all three classes was used to analyze HERV transcription patterns in three persistently HIV-1 infected cell lines of different cellular origins and in their uninfected counterparts. All three persistently infected cell lines showed increased transcription of multiple class I and II HERV groups. Up-regulated transcription of five HERV taxa (HERV-E, HERV-T, HERV-K (HML-10) and two ERV9 subgroups) was confirmed by quantitative reverse transcriptase PCR analysis and could be reversed by knock-down of HIV-1 expression with HIV-1-specific siRNAs. Cells infected de novo by HIV-1 showed stronger transcriptional up-regulation of the HERV-K (HML-2) group than persistently infected cells of the same origin. Analysis of transcripts from individual members of this group revealed up-regulation of predominantly two proviral loci (ERVK-7 and ERVK-15) on chromosomes 1q22 and 7q34 in persistently infected KE37.1 cells, as well as in de novo HIV-1 infected LC5 cells, while only one single HML-2 locus (ERV-K6) on chromosome 7p22.1 was activated in persistently infected LC5 cells.

Conclusions: Our results demonstrate that HIV-1 can alter HERV transcription patterns of infected cells and indicate a correlation between activation of HERV elements and the level of HIV-1 production. Moreover, our results suggest that the effects of HIV-1 on HERV activity may be far more extensive and complex than anticipated from initial studies with clinical material.

Show MeSH
Related in: MedlinePlus