Genetics Commons^™

The Purification Of Ribosomal Rna Gene Chromatin From Physarum Polycephalum, Sally A. Amero, Roy C. Ogle, John L. Keating, Vicky L. Montoya, Wendy L. Murdoch, Robert M. Grainger

School of Medical Diagnostics & Translational Sciences Publications

We have undertaken the purification of ribosomal RNA gene (rDNA) chromatin from the slime mold Physarum polycephalum, in order to study its chromatin structure. In this organism rDNA exists in nucleoli as highly repeated minichromosomes, and one can obtain crude chromatin fractions highly enriched in rDNA from isolated nucleoli. We first developed a nucleolar isolation method utilizing polyamines as stabilization agents that results in a chromatin fraction containing far more protein than is obtained by the more commonly used divalent cation isolation methods. The latter method appears to result in extensive histone loss during chromatin isolations. Two methods were then …

The Homeo Domain Of A Murine Protein Binds 5' To Its Own Homeo Box., Abraham Fainsod, Leonard D. Bogarad, Tarmo Ruusala, Martin Lubin

Dartmouth Scholarship

Nuclear protein extracts from day 12.5 mouse embryos were used to study protein binding to DNA sequences 5' of the Hox 1.5 homeo box. Embryos of this developmental stage are known to express this gene. DNA binding protein blotting and retardation gel techniques show that murine embryonic nuclear proteins specifically bind a 753-base pair (bp) DNA fragment from the region upstream of the Hox 1.5 homeo box. A fusion protein containing the Hox 1.5 homeo domain constructed in lambda gt11 also binds the same 753-bp DNA fragment. Specific binding of the fusion protein to the upstream DNA fragment shows that …

Genetically Controlled Variation Of “Acid” Beta-Galactosidase Detected In Rattus Norvegicus By Isoelectric Focusing, T C Douglas, K A Kimmel, P E Dawson

Faculty, Staff and Student Publications

Two genetically variant forms of rat "acid" beta-galactosidase were found to differ in isoelectric point and pH dependence, but not in thermostability or sensitivity to inhibition by p-mercuribenzoate (PMB). The results of two backcrosses and an intercross indicated that the isoelectric focusing phenotypes are controlled by two codominant alleles at a single autosomal locus, for which we propose the name Glb-1. No significant linkage between Glb-1 and albino (LG I), brown (LG II), or hooded (LG VI) was observed. Strain-specific differences in total levels of kidney beta-galactosidase were detected, but it is not yet known whether the variation is controlled …

Polymorphisms, Linkage And Mapping Of Four Enzyme Loci In The Fish Genus Xiphophorus (Poeciliidae), D C Morizot, M J Siciliano

Faculty, Staff and Student Publications

Electrophoretic variants at four additional enzyme loci--two esterases (Est-2, Est-3), retinal lactate dehydrogenase (LDH-1) and mannose phosphate isomerase (MPI)--among three species and four subspecies of fish of the genus Xiphophorus were observed. Electrophoretic patterns in F1 hybrid heterozygotes confirmed the monomeric structures of MPI and the esterase and the tetrametric structure of LDH in these fishes. Variant alleles of all four loci displayed normal Mendelian segregation in backcross and F2 hybrids. Recombination data from backcross hybrids mapped with Haldane's mapping function indicate the four loci to be linked as Est-2--0.43--Est3--0.26--LDH-1--0.19--MPI. Significant interference was detected and apparently concentrated in the Est-3 …

Modification Of Ontogenic Expression Due To Relocation Of The Ry+ Gene In Drosophila Melanogaster, Allen A. Badgett Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The ry⁺ gene of Drosophila melanogaster and its associated enzyme, xanthine dehydrogenase, were employed in an analysis of the relationship between regulation and the location of a gene in the genome. Enzyme assays as an indication of gene activity were performed on genotypes containing zero, one and two doses of ry⁺ genes. Xanthine dehydrogenase activity of rosy genes in normal and relocated positions was determined during development.

The results indicate: 1) the gene ry⁺ is differentially active during ontogeny; 2) the activity during ontogeny is proportional to the number of ry⁺ genes present in the genome; …