title: Contribution of AT-, GC-, and methylated cytidine-rich DNA to chromatin composition in Malpighian tubule cell nuclei of Panstrongylus megistus (Hemiptera, Reduviidae).
abstract: The Malpighian tubule cell nuclei of male Panstrongylus megistus, a vector of Chagas disease, contain one chromocenter, which is composed solely of the Y chromosome. Considering that different chromosomes contribute to the composition of chromocenters in different triatomini species, the aim of this study was to determine the contribution of AT-, GC-, and methylated cytidine-rich DNA in the chromocenter as well as in euchromatin of Malpighian tubule cell nuclei of P. megistus in comparison with published data for Triatoma infestans. Staining with 4',6-diamidino-2-phenylindole/actinomycin D and chromomycin A(3)/distamycin, immunodetection of 5-methylcytidine and AgNOR test were used. The results revealed AT-rich/GC-poor DNA in the male chromocenter, but equally distributed AT and GC DNA sequences in male and female euchromatin, like in T. infestans. Accumulation of argyrophilic proteins encircling the chromocenter did not always correlate with that of GC-rich DNA. Methylated DNA identified by immunodetection was found sparsely distributed in the euchromatin of both sexes and at some points around the chromocenter edge, but it could not be considered responsible for chromatin condensation in the chromocenter, like in T. infestans. However, unlike in T. infestans, no correlation between the chromocenter AT-rich DNA and nucleolus organizing region (NOR) DNA was found in P. megistus.
authors.affiliation: Structural and Physiological Biology for Anatomy, Cell Biology and Physiology, Institute of Biology, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil.
authors.forename: Elenice M
authors.initials: EM
authors.lastname: Alvarenga
authors.forename: Mateus
authors.initials: M
authors.lastname: Mondin
authors.forename: Vera L C C
authors.initials: VL
authors.lastname: Rodrigues
authors.forename: Larissa M
authors.initials: LM
authors.lastname: Andrade
authors.forename: Benedicto de Campos
authors.initials: Bde C
authors.lastname: Vidal
authors.forename: Maria Luiza S
authors.initials: ML
authors.lastname: Mello
mesh_terms: D020856:AT Rich Sequence; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D002478:Cells, Cultured; D002843:Chromatin / Q000235:genetics*; D003562:Cytidine / Q000031:analogs & derivatives / Q000378:metabolism; D019175:DNA Methylation; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D020862:GC Rich Sequence; D017344:Genes, Insect; D008297:Male; D008317:Malpighian Tubules / Q000166:cytology*; D051379:Mice; D009697:Nucleolus Organizer Region / Q000378:metabolism; D009758:Nymph / Q000166:cytology / Q000235:genetics; D010203:Panstrongylus / Q000166:cytology / Q000235:genetics*
chemical_list: D002843:Chromatin; D003562:Cytidine; C016568:5-methylcytidine