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Comparative expression analysis of human endogenous retrovirus elements in peripheral blood of children with specific language impairment

DS Minchev
DS Minchev
, 
NT Popov
NT Popov
, 
SI Naimov
SI Naimov
, 
IN Minkov
IN Minkov
 and 
TI Vachev
TI Vachev
   | Aug 28, 2019
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Article Category: Original Article
Published Online: Aug 28, 2019
Page range: 49 - 56
DOI: https://doi.org/10.2478/bjmg-2019-0014
Keywords
© 2019 Minchev DS, Popov NT, Naimov SI, Minkov IN, Vachev TI, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Figure 1

Melting (dissociation) curve analysis of the five HERV-encoded genes and the endogenous control used for normalization. A specific single peak was detected in the dissociation curves for all amplicons in every SLI and control sample. Panel A: HERV-K (HML-2) gag amplicons with a melting temperature 80.4 °C ± 1 °C. Panel B: HERV-K em with a melting temperature 77.7 °C ± 1 °C. Panel C: HERV-P em amplicons with a melting temperature 78.7 °C ± 1 °C. Panel D: HERV-R em with a melting temperature 77.9 °C ± 1 °C. Panel E: HERV-Wpo/ amplicons with a melting temperature 76.9 °C ± 1 °C. Panel F: GAPDH with a melting temperature 80.8 °C ± 1 °C.
Melting (dissociation) curve analysis of the five HERV-encoded genes and the endogenous control used for normalization. A specific single peak was detected in the dissociation curves for all amplicons in every SLI and control sample. Panel A: HERV-K (HML-2) gag amplicons with a melting temperature 80.4 °C ± 1 °C. Panel B: HERV-K em with a melting temperature 77.7 °C ± 1 °C. Panel C: HERV-P em amplicons with a melting temperature 78.7 °C ± 1 °C. Panel D: HERV-R em with a melting temperature 77.9 °C ± 1 °C. Panel E: HERV-Wpo/ amplicons with a melting temperature 76.9 °C ± 1 °C. Panel F: GAPDH with a melting temperature 80.8 °C ± 1 °C.

Figure 2

Differential expression of HERV in children with SLI (data presented in logarithmic scale). The qRT-PCR analysis of gene expression revealed that levels of HERV-K (HML-2) gag and HERV-P env were at least 1.4-times lower in the children with SLI compared to those in the control group (1.41- and 1.67-fold change for HERV-K (HML-2) gag and HERV-P env, respectively). Quantitative evaluation of the other three genes: HERV-K env, HERV-R env and HERV-W pol, found no significant changes in expression between the two groups.
Differential expression of HERV in children with SLI (data presented in logarithmic scale). The qRT-PCR analysis of gene expression revealed that levels of HERV-K (HML-2) gag and HERV-P env were at least 1.4-times lower in the children with SLI compared to those in the control group (1.41- and 1.67-fold change for HERV-K (HML-2) gag and HERV-P env, respectively). Quantitative evaluation of the other three genes: HERV-K env, HERV-R env and HERV-W pol, found no significant changes in expression between the two groups.

Figure 3

Relative quantitation of differentially expressed HERV genes in SLI children and healthy controls. Data is presented in box plot diagrams with linear scale. The HERV levels in the control are normalized to 1.
Relative quantitation of differentially expressed HERV genes in SLI children and healthy controls. Data is presented in box plot diagrams with linear scale. The HERV levels in the control are normalized to 1.

Figure 4

Receiver operating characteristic curve analysis on differential expression data for HERV-K (HML-2) gag and HERV-P env The ROC curves were calculated using MedCalc (https://www.mecalc.org) commercial statistical software. Random predictive accuracy (AUC value of 0.5 that corresponds to a 50.0% chance of discrimination by pure guessing) is denoted by a diagonal line. The ROC curves were plotted for HERV-K (HML-2) gag and HERV-P em that yielded 0.828 and 0.858 AUC values, respectively.
Receiver operating characteristic curve analysis on differential expression data for HERV-K (HML-2) gag and HERV-P env The ROC curves were calculated using MedCalc (https://www.mecalc.org) commercial statistical software. Random predictive accuracy (AUC value of 0.5 that corresponds to a 50.0% chance of discrimination by pure guessing) is denoted by a diagonal line. The ROC curves were plotted for HERV-K (HML-2) gag and HERV-P em that yielded 0.828 and 0.858 AUC values, respectively.

The HERV-specific qRT-PCR primer pairs.

HERV GeneForward Primer (5'>3')Reverse Primer (5'>3')
HERV (HML-2) gagGGC CAT CAG AGT CTA AAC CAC GCTG ACT TTC TGG GGG TGG CCG
HERV-K envGGG TAC CTG GCC CCA TAG ATCAT CAT CCC TTC TTC CTC AGG TT
HERV-W polTGA GTC AAT TCT CAT ACC TGAGT TAA GAG TTC TTG GGT GG
HERV-P envCAA GAT TGG GTC CCC TCA CCCT ATG GGG TCT TTC CCT G
HERV-R emCAT GGG AAG CAA GGG AAC ΤCTT TCC CCA GCG AGC AAT AC
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