B-chromosome effects on Hsp70 gene expression does not occur at transcriptional level in the grasshopper Eyprepocnemis plorans
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As intragenomic parasites, B chromosomes can elicit stress in the host genome, thus inducing a response for host adaptation to this kind of continuous parasitism. In the grasshopper Eyprepocnemis plorans, B-chromosome presence has been previously associated with a decrease in the amount of the heat-shock protein 70 (HSP70). To investigate whether this effect is already apparent at transcriptional level, we analyze the expression levels of the Hsp70 gene in gonads and somatic tissues of males and females with and without B chromosomes from two populations, where the predominant B chromosome variants (B2 and B24) exhibit different levels of parasitism, by means of quantitative real-time PCR (qPCR) on complementary DNA (cDNA). The results revealed the absence of significant differences for Hsp70 transcripts associated with B-chromosome presence in virtually all samples. This indicates that the decrease in HSP70 protein levels, formerly reported in this species, may not be a consequence of transcriptional down-regulation of Hsp70 genes, but the result of post-transcriptional regulation. These results will help to design future studies oriented to identifying factors modulating Hsp70 expression, and will also contribute to uncover the biological role of B chromosomes in eukaryotic genomes.
KeywordsB chromosomes Gene expression Hsp70 Intragenomic parasites qPCR Stress
We thank two anonymous reviewers for useful comments.
Compliance with ethical standards
This study was funded by the Spanish Ministerio de Economía y Competitividad (CGL2015-70750-P) and Plan Andaluz de Investigación (CVI-6649). B. Navarro-Domínguez was supported by an FPI fellowship from the Spanish Ministerio de Ciencia e Innovación (BES-2010-030016).
Conflict of interest
B. Navarro-Domínguez declares that she has no conflict of interest. J. Cabrero declares that she has no conflict of interest. J. P. M. Camacho declares that he has no conflict of interest. M.D. López-León declares that she has no conflict of interest.
All applicable institutional and national guidelines for the care and use of animals were followed.
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