MicroRNAs (miRNAs) are small noncoding RNAs of about 19–25 nt that regulate gene expression posttranscriptionally under various cellular conditions, including apoptosis. The miRNAs involved in modulation of apoptotic events in T cells are partially known. | Turkish Journal of Biology Research Article Turk J Biol (2018) 42: 113-122 © TÜBİTAK doi: Deep sequencing reveals two Jurkat subpopulations with distinct miRNA profiles during camptothecin-induced apoptosis İpek ERDOĞAN, Mehmet İlyas COŞACAK, Ayten NALBANT, Bünyamin AKGÜL* Department of Molecular Biology and Genetics, İzmir Institute of Technology, Gülbahçeköyü, Urla, İzmir, Turkey Received: Accepted/Published Online: Final Version: Abstract: MicroRNAs (miRNAs) are small noncoding RNAs of about 19–25 nt that regulate gene expression posttranscriptionally under various cellular conditions, including apoptosis. The miRNAs involved in modulation of apoptotic events in T cells are partially known. However, heterogeneity associated with cell lines makes it difficult to interpret gene expression signatures, especially in cancer-related cell lines. Treatment of the Jurkat T-cell leukemia cell line with the universal apoptotic drug, camptothecin, resulted in identification of two Jurkat subpopulations: one that is sensitive to camptothecin and another that is rather intrinsically resistant. We sorted apoptotic Jurkat cells from nonapoptotic ones prior to profiling miRNAs through deep sequencing. Our data showed that a total of 184 miRNAs were dysregulated. Interestingly, the apoptotic and nonapoptotic subpopulations exhibited distinct miRNA expression profiles. In particular, 6 miRNAs were inversely expressed in these two subpopulations. The pyrosequencing results were validated by real-time qPCR. Altogether, these results suggest that miRNAs modulate apoptotic events in T cells and that cellular heterogeneity requires careful interpretation of miRNA expression profiles obtained from drug-treated cell lines. Key words: Apoptosis, microRNAs, Jurkat, deep sequencing 1. Introduction Apoptosis is programmed cell death triggered by various stimuli from outside or inside the cell,