SELECTIVE INHIBITION OF GENETIC TRANSCRIPTION IN SEA URCHIN EMBRYOS Incorporation of 5-Bromodeoxyuridine into Low Molecular Weight Nuclear DNA
نویسنده
چکیده
Experimental evidence suggests that exposure of sea urchin gastrulae to 5-bromodeoxyuridine (BUdR), an analog of thymidine, causes a reduction in the rate of synthesis of some RNA species usually transcribed at this stage of development . In pulse-chase experiments, 3H (in gastrula stage 8-15S nuclear DNA labeled with BUdR3H) could not be chased, with unlabeled BUdR, into 20-60S size-range DNA ; in similar experiments in which gastrulae were pulsed with thymidine 3H and then chased with unlabeled thymidine, 3H in 8-15S nuclear DNA could be extensively chased into 20-60S DNA. DNA-RNA hybridization assays indicate that gastrula stage nuclear DNA in the range of 20-60S has greater sequence homology for gastrula stage RNA-3H than does nuclear DNA of similar size-range taken from gastrulae exposed to BUdR for 1 hr . An explanation is offered for the effect of BUdR on transcription and DNA replication in sea urchin embryos .
منابع مشابه
Selective Inhibition of Genetic Transcription in Sea Urchin Embryos
Experimental evidence suggests that exposure of sea urchin gastrulae to 5-bromodeoxyuridine (BUdR), an analog of thymidine, causes a reduction in the rate of synthesis of some RNA species usually transcribed at this stage of development. In pulse-chase experiments, (3)H (in gastrula stage 8-15S nuclear DNA labeled with BUdR-(3)H) could not be chased, with unlabeled BUdR, into 20-60S size-range ...
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