Inhibition of RNA synthesis in Drosophila embryos by isoxanthopterin


In the investigation of possible relationships between changes in concentration of the pteridine xanthopterin and discontinuous rRNA synthesis during embryogenesis of OncopeItus fasciatus, Harris and Forrest (1967) observed that an isomer, isoxanthopterin, was more effective than xanthopterin in inhibiting both rRNA and DNA synthesis. It was subsequently shown that isoxanthopterin, which is present in developing embryos of the insect, also inhibits synthesis of 5S RNA and tRNA (Smith and Forrest, 1971). Lagowski and Forrest (1967) demonstrated that isoxanthopterin binds to DNA in a manner enhancing fluorescence of the pteridine and that actinomycin D is an ineffective competitor in this binding. Two considerations make the biological significance of these findings difficult to evaluate. Oncopeltus eggs normally contain relatively high levels of isoxanthopterin, the concentration of which does not fluctuate very widely during embryogenesis (Forrest et al., 1966). In addition, the concentrations of isoxanthopterin used in vitro have been at least a hundredfold greater than the concentration of actinomycin D required to inhibit rRNA synthesis by more than 80% (Penman et al., 1970). A focus of interest in this laboratory has been the regulation of rRNA metabolism in Drosophila melanogaster. Our interest in isoxanthopterin arose in relation to investigation of the rescuable, female-sterile mutant, dor

DOI: 10.1007/BF00486001

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@article{Puckett1975InhibitionOR, title={Inhibition of RNA synthesis in Drosophila embryos by isoxanthopterin}, author={Lindsey Puckett and Linda A. Snyder}, journal={Biochemical Genetics}, year={1975}, volume={13}, pages={1-6} }