A novel mitochondrial DNA-like sequence insertion polymorphism in Intron I of the FOXO1A gene Claudia Giampieri a,1 , Matteo Centurelli a,1 , Massimiliano Bonafe ` b , Fabiola Olivieri a , Maurizio Cardelli a , Francesca Marchegiani a , Luca Cavallone a , Simona Giovagnetti a , Elena Mugianesi a , Giuseppina Carrieri a , Rosamaria Lisa a , Stefano Cenerelli a , Roberto Testa a , Massimo Boemi a , Chariklia Petropoulou c , Efstathios S. Gonos c , Claudio Franceschi a,b, * a Department of Research and Diabetology Unit, Italian National Research Centers on Ageing, Via Birarelli 8, Ancona 60124, Italy b Department of Experimental Pathology, Bologna University, Bologna, Italy c Laboratory of Molecular and Cellular Ageing, Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, Athens, Greece Received 4 June 2003; received in revised form 3 October 2003; accepted 7 November 2003 Received by G. Pesole Abstract The human forkhead box O1A (FOXO1A) gene belongs to the human forkhead gene family and acts downstream of the human insulin signalling pathway. In this study, polymorphisms of the Intron I of FOXO1A gene were studied in Italian healthy people and insulin resistant subjects. No significant association between the germ-line variability in the Intron I of FOXO1A and insulin resistance was observed. Interestingly, during the study, a new 39-bp sequence insertion polymorphism in Intron I of FOXO1A gene was described. The polymorphism was found to co-segregate in a co-dominant Mendelian fashion and to be present in an ethnically distinct population (Greeks). A BLAST search showed that the sequence shares 100% identity with a mtDNA (mithocondrial DNA) sequence coding for the ATP synthase 8 (ATPase8) and ATP synthase 6 (ATPase6) genes. Hence, FOXO1A Intron I is a polymorphic nuclear region involved in the exchange of DNA material between mitochondrial and genomic DNA, which is a well-established mechanism of evolutionary change in eukaryotes. D 2004 Elsevier B.V. All rights reserved. Keywords: SNP; Insertion/deletion; mtDNA; Heritability; Insulin resistance; Transposable element 1. Introduction The human forkhead box O1A (FOXO1A) gene (also termed FKHR) belongs to the forkhead DNA-binding pro- tein family (Lai et al., 1993). The gene is located on chromosome 13q14.1 and it was first identified as a product fusion with the PAX3 gene (t(2;13) translocation) found in the paediatric soft tissue tumour alveolar rhabdomyosarco- ma (Galili et al., 1993). FKHR-like genes are the human homologues of the Daf-16 Caenorhabditis elegans gene, which is involved in an insulin-related signalling pathway regulating metabolism, development and life-span in the worm (Ogg et al., 1997). In humans, the product of the FOXO1A gene has been shown to be regulated by proteins, like PKB/Akt, belonging to the insulin signalling pathway (Nakae et al., 1999), and insulin was shown to inhibit gene transcription by stimulating the phosphorilation and nuclear export of FOXO1A (Biggs et al., 1999; Hall et al., 2000). We report here a comparative study on DNA polymor- phism of FOXO1A Intron I gene in healthy Italian people and patients affected by insulin resistance (Kinney, 2002). Moreover, we describe a new 39-bp insertion polymorphism 0378-1119/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.gene.2003.11.003 Abbreviations: FOXO1A, forkhead box O1A; mtDNA, mithocondrial DNA; ATPase8, ATP synthase 8; ATPase6, ATP synthase 6; FKHR, forkhead in rhabdomyosarcoma gene; PAX3, paired box gene 3; Daf-16, dauer formation gene 16; PKB/Akt, protein kinase B/Akt; bp, base pairs; PCR, polymerase chain reaction; dNTP, deoxynucleotide triphosphate; SNP, single nucleotide polymorphism; SINE, short interspersed nuclear element; MIR, mammalian-wide interspersed repeat. * Corresponding author. Direzione Scientifica, Italian National Re- search Centers on Ageing, Villa Gusso, Via S. Margherita 5, Ancona 60124, Italy. Tel.: +39-071-8004764; fax: +39-071-206791. E-mail address: clafra@kaiser.alma.unibo.it (C. Franceschi). 1 These authors contributed equally to the manuscript. www.elsevier.com/locate/gene Gene 327 (2004) 215 – 219