Chromosome Banding in Amphibia. XXXIII. Demonstration of 5-Methylcytosine-Rich Heterochromatin in Anura

Abstract

An experimental approach using monoclonal anti-5-methylcytosine (5-MeC) antibodies and indirect immunofluorescence was elaborated for detecting 5-MeC-rich chromosome regions in anuran chromosomes. This technique was applied to mitotic metaphases of 6 neotropical frog species belonging to 6 genera and 4 families. The hypermethylation patterns were compared with a variety of banding patterns obtained by conventional banding techniques. The hypermethylated DNA sequences are species-specific and located exclusively in constitutive heterochromatin. They are found in centromeric, pericentromeric, telomeric, and interstitial positions of the chromosomes and adjacent to nucleolus organizer regions. 5-MeC-rich DNA sequences can be embedded both in AT- and GC-rich repetitive DNA. The experimental parameters that have major influence on the reproducibility and quality of the anti-5-MeC antibody labeling are discussed.

Chromosome Banding in Amphibia. XXXV. Highly Mobile Nucleolus Organizing Regions in Craugastor fitzingeri (Anura, Craugastoridae)

“…In this species, 5-methylcytosine-rich heterochromatin is confined to pericentromeric positions in the chromosomes 2, 3, and 12 [Schmid and Steinlein, 2016].…”

“…Hypermethylated DNA was detected using a monoclonal antibody against 5-methylcytosine and the technique of indirect immunofluorescence as modified by Schmid and Steinlein [2016]. Image analysis was performed with Zeiss epifluorescence microscopes equipped with thermoelectronically cooled charge-coupled device cameras (Applied Spectral Imaging) using easyFISH 1.2 software.…”

Karyotype and Mapping of Repetitive DNAs in the African Butterfly Fish <b><i>Pantodon buchholzi, </i></b>the Sole Species of the Family Pantodontidae

“…Conventional staining was done using 5% Giemsa solution in phosphate buffer pH 6.8 for 10 min. The Cbanding method was used to demonstrate C-positive heterochromatin [Sumner, 1972], silver staining to detect AgNORs [Howell and Black, 1980], and chromomycin A 3 (CMA 3 ) staining to show GC-rich chromosome regions [Schmid, 1980].…”

Cytogenetic characterization of species of the family Heptapteridae (Teleostei: Siluriformes) from the Cuiabá and Ivaí River Basins, Brazil

“…We obtained 18S rDNA probes by amplifying and cloning fragments from Oreochromis niloticus. Base-specific fluorochrome staining methods using chromomycin A 3 (CMA 3 ) and 4ꞌ,6-diamidino-2-phenylindole (DAPI) were performed, according to the methods described by Schmid (1980) and Schweizer (1976), respectively. The distribution patterns of heterochromatin were ascertained following the technique described by Sumner (1972).…”