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Epstein-Barr Virus Transformation of Human Lymphoblastoid Cells from Patients with Fragile X Syndrome Induces Variable Changes on CGG Repeats Size and Promoter Methylation

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Abstract

Background: Our understanding of fragile X syndrome can be improved by reversing the expression of the silenced fragile X mental retardation 1 (FMR1) gene in immortalized cells from these patients. Epstein-Barr virus (EBV) infection has been extensively used to transform B cells into a permanent lymphoblastoid cell line.

Methods: We immortalized B lymphocytes from three different fragile X patients and one normal male. We analyzed the CGG triplet repeats and methylation status of the FMR1 and interferon (IFN)-γ promoter. We also assayed FMR1 mRNA levels by real-time PCR and FMR1 protein (FMRP) by Western blot.

Results: We observed that EBV transformation may induce the instability of CGG repeats and DNA demethylation that can lead to the modification of mRNA expression.

Conclusions: EBV transformation may induce variable changes in the genome that can lead to the misinterpretations of experimental data obtained from these cells. Thus, periodic testing of DNA from immortalized cells should be routinely undertaken to detect undesired effects.

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Acknowledgements

We are very grateful to Dr R. Fernández-Muñoz (Laboratorio de Virología, Hospital Ramón y Cajal, Madrid) for the EBV aliquots used in this study and for his useful advice on how to manipulate them. We thank Dr J.L. Mandel (INSERM, Strasburg, France) for the StB12.3 probe. We also wish to thank to Dr M. Carrasco (Ministry of Education of the Andelusian Government, Huelva, Spain) for the IQ data. We would like to express our gratitude to Dr J. López-Barneo (LIB, Seville) for his advise in the writing of the manuscript and for his generosity in making the ABI Prism 7000 available.

This work was supported by grants 01/1132 from the Ministerio de Sanidad y Consumo and 80/01 from the Servicio Andaluz de Salud, Spain.

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Authors and Affiliations

  1. Department of Biochemical Medicine and Molecular Biology, Faculty of Medicine and University Hospital of the Virgin Macarena, University of Seville, Seville, Spain

    Victoria Bonilla, Francisco Sobrino, Miguel Lucas &  Elizabeth Pintado

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  1. Victoria Bonilla
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  2. Francisco Sobrino
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  3. Miguel Lucas
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  4. Elizabeth Pintado
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Correspondence to Elizabeth Pintado.

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Bonilla, V., Sobrino, F., Lucas, M. et al. Epstein-Barr Virus Transformation of Human Lymphoblastoid Cells from Patients with Fragile X Syndrome Induces Variable Changes on CGG Repeats Size and Promoter Methylation. CNS Drugs 7, 163–167 (2003). https://doi.org/10.1007/BF03260033

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