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R E Ganschow

Publications and source records attributed to R E Ganschow.

28 records · Page 2Linked to original sources
PubMed1978

Turnover of murine beta-glucuronidase. Comparison among liver, kidney, and spleen and between lysosomes and microsomes.

The turnover properties of murine beta-glucuronidase in several tissues and at two subcellular sites have been determined by monitoring the radioactivity present in immunoprecipitated enzyme at a number of time points following the in vivo administration of a single radiolabeled protein precursor (either L-[3,4(-3H)]leucine or or NaH14CO3). In all experiments a considerable period of time was required for the attainment of maximum specific radioactivity in glucuronidase. Similar labeling kinetics was found when [3H]leucine incorporation was monitored in immunoprecipitated murine liver delta-aminolevulinate dehydratase. Half-life estimates of 2 to 3 days were obtained for glucuronidases of liver, kidney, and spleen. In most strains of inbred mice, it is known that approximately 60% of total liver glucuronidase activity resides in lysosomes, while 40% is within the membranes of the endoplasmic reticulum (Ganschow, R. E. and Paigen, K. (1968) Genetics 59, 335-349). These two subcellular forms of glucuronidase turn over at similar rates. Furthermore, the bulk of glucuronidase in the endoplasmic reticulum does not serve as precursor to lysosomal glucuronidase.

Animals↗
PubMed1978

Zinc deficiency in murine milk underlies expression of the lethal milk (lm) mutation.

The inability of nursing pups to survive on milk of mice homozygous for the recessive mutation, lethal milk (lm), is correlated with a reduction in zinc levels of both milk and pup carcass. Administration of zinc to pups nursing on lmlm dams reduces the observed mortality and morbidity. It is suggested that lm alters zinc transport from maternal blood to milk and that its study may provide useful information for understanding the rare human disease, acrodermatitis enteropathica.

Animals↗
PubMed1978

Apparent trans control of murine beta-glucuronidase synthesis by a temporal genetic element.

A difference in the heat-inactivation kinetics between the beta-glucuronidases of C3HeB/FeJ and C57B1/6J mice was utilized to assess the mode of action of a temporal genetic element in controlling the expression of the beta-glucuronidase structural gene Gus. The heat-inactivation kinetics of liver and kidney beta-glucuronidase from F1 C3HeB/FeJ X C57B1/6J animals were intermediate with respect to the parental enzyme patterns, suggesting that equal concentrations of the two allelic products were present in beta-glucuronidase tetramers of F1 progeny. beta-glucuronidase heteropolymers assembled in vivo under conditions where equal concentrations of the two structural alleles of the enzyme were known to be present also exhibited intermediate heat-inactivation kinetics. These observations are consistent with a trans mode of action of a genetic element that controls the rate of murine beta-glucuronidase synthesis.

Alleles↗
PubMed1975

The molecular genetics of mammalian glucuronidase.

The genetic factors known to be involved in the final realization of beta-glucuronidase activity in mice are considered from the standpoint of structural genes determining the catalytic activity of enzyme molecules as well as the recognition features of enzyme molecules that identify them for subsequent processing by the cell; processing genes determining the cellular apparatus involved with the conjugation, intracellular localization and eventual degradation of enzyme molecules; regulatory genes determining rates of enzyme synthesis, especially in response to physiological signals such as hormones; and temporal genes determining the developmental programs for expression of these classes during growth and differentiation. The properties of genetic variants of beta-glucuronidase falling into each of these classes are described. When those results are considered in concert with the properties of genetic variants known for other mammalian enzymes several generalizations emerge. Structural genes of enzymes are not usually linked to the processing genes determining the post-assembly events in the life of that enzyme. In contrast, all of the regulatory and temporal gene sites so far identified are in close proximity to the structural genes they modulate. Regulatory and temporal sites appear to act in a cis fashion to control the amount of enzyme synthesized from the adjacent structural allele on the same chromosome.

Animals↗