title: Studying epigenetic DNA modifications in undergraduate laboratories using complementary bioinformatic and molecular approaches.
abstract: Epigenetic inheritance is the inheritance of genetic information that is not based on DNA sequence alone. One type of epigenetic information that has come to the forefront in the last few years is modified DNA bases. The most common modified DNA base in nature is 5-methylcytosine. Herein, we describe a laboratory experiment that combines bioinformatic and molecular approaches to study the presence and abundance of 5-methylcytosine in different organisms. Students were originally provided with the protein sequence of the Xenopus laevis DNMT1 cytosine-5 DNA methyltransferase and used BLASTP searches to detect the presence of protein orthologs in the genomes of several organisms including Homo sapiens, Mus musculus, Plasmodium falciparum, Drosophila melanogaster, Saccharomyces cerevisiae, Arabidopsis thaliana, and Caenorhabditis elegans. Students generated hypotheses regarding the presence and abundance of 5-methylcytosine in these organisms based on their bioinformatics data, and directly tested their predictions on a subset of DNAs using restriction enzyme isoschizomer assays. A southern blotting assay to answer the same question is also presented. In addition to exposure to the field of epigenetics, the strengths of the laboratory are students are able to make predictions using bioinformatic tools and quickly test them in the laboratory. In addition, students are exposed to two potential misinterpretations of bioinformatic search data. The laboratory is easily modified to incorporate outside research interests in epigenetics.
authors.affiliation: Biology Department, State University of New York at Geneseo, ISC 357, 1 College Circle, Geneseo, New York, 14454.
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Militello
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000235:genetics; D017173:Caenorhabditis elegans / Q000235:genetics; D019295:Computational Biology / Q000193:education*; D004247:DNA / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics; D044127:Epigenesis, Genetic / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D007753:Laboratories; D051379:Mice; D008967:Molecular Biology / Q000193:education*; D041681:NIH 3T3 Cells; D010963:Plasmodium falciparum / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013334:Students; D014495:Universities
chemical_list: D004247:DNA
keywords: 5-methylcytosine; DNA methylation; cytosine-5 DNA methyltransferase