Biochemical Genetics, Vol. 41, Nos. 7/8, August 2003 ( C  2003) A High Mobility Group Protein From the Dipteran Insects Ceratitis capitata and Bactrocera oleae Vassiliki Aleporou-Marinou, 1,2 Christina Deli, 1 Yiannis Ninios, 1 Barbara Agelopoulou, 1 Haroula Marinou, 1 and Theocharis Patargias 1 Received 7 June 2002—Final 7 June 2002 Nuclei from Bactrocera oleae and Ceratitis capitata larvae contain a major protein that shares most of the characteristics of vertebrate high mobility group (HMG) proteins. Proteins are extracted from nuclei with 0.35 M NaCl, are soluble in 5% perchloric acid, are relatively small (molecular weight in the range of 10–16 kDa), and have both a high basic and a high acidic amino acid content. The amino acid constitution of these proteins is similar to that of the HMGB protein family of vertebrates. The proteins cross-react with antibodies raised against the HMGD chromosomal protein of Drosophila melanogaster. The possible relatedness of these proteins to high mobility group proteins is discussed. KEY WORDS: HMG proteins; high mobility group-like proteins; polyacrylamide electrophoresis; western immunoblotting. INTRODUCTION The high mobility group (HMG-motif) proteins are an abundant class of chromoso- mal proteins. The mammalian HMG proteins have been grouped into three distinct families on the basis of their characteristic functional sequence: the HMGB, the HMGN, and the HMGA family (previously HMG1/2, HMG14/17, HMGI/Y) (for detailed reviews, see Bianchi, 1995; Bustin, 1999; Bustin et al., 1990; Bustin and Reeves, 1996). Originally identified in the early 1960s as acidic impurities in histone H1 preparation (Johns, 1964), HMG proteins and their genes from a variety of vertebrates have been isolated and characterized (Bustin et al., 1990). 1 Department of Biology, Division of Genetics and Biotechnology, University of Athens, Panepistimiopolis 15701, Athens, Greece. 2 To whom correspondence should be addressed; e-mail: valepor@biol.uoa.gr. 235 0006-2928/03/0800-0235/0 C  2003 Plenum Publishing Corporation