Anucleate HTC cells have been used to determine the importance of the nucleus in the regulation o... more Anucleate HTC cells have been used to determine the importance of the nucleus in the regulation of the intracellular levels of tyrosine aminotransferase (TAT) in hepatoma tissue culture (HTC) cells. In the absence of the nucleus, neither the induction of the enzyme by dexamethasone nor its deinduction upon removal of the hormone occurs. Degradation of the enzyme takes place when protein synthesis is inhibited in anucleates by cycloheximide. Therefore, the maintenance of induced levels of enzyme activity after dexamethasone withdrawal from pre-induced anucleates suggest that the nucleus is required for the inactivation of the TAT mRNA.
We have tested the ability of polyvinyl alcohol (PVA) to enhance the indoxyl-nitro blue tetrazoli... more We have tested the ability of polyvinyl alcohol (PVA) to enhance the indoxyl-nitro blue tetrazolium alkaline phosphatase color reaction in whole mount in situ hybridizations of early stage quail embryos. Using detection of the myogenic factor qmyoD in hybridizations of 13-14 somite-pair quail embryos as a test system, 10% solutions of 13-23 kDa and 31-50 kDa PVA optimally enhanced the alkaline phosphatase color reaction. With the enhanced detection conditions, we have been able to measure qmyoD expression as early as the 3 somite-pair stage, whereas previously we were unable to detect qmyoD prior to the 10 somite-pair stage. PVA-enhanced detection of somitic qmyoD expression was specific as no corresponding signal was found in control hybridizations with a sense qmyoD probe.
Anucleate HTC cells have been used to determine the importance of the nucleus in the regulation o... more Anucleate HTC cells have been used to determine the importance of the nucleus in the regulation of the intracellular levels of tyrosine aminotransferase (TAT) in hepatoma tissue culture (HTC) cells. In the absence of the nucleus, neither the induction of the enzyme by dexamethasone nor its deinduction upon removal of the hormone occurs. Degradation of the enzyme takes place when protein synthesis is inhibited in anucleates by cycloheximide. Therefore, the maintenance of induced levels of enzyme activity after dexamethasone withdrawal from pre-induced anucleates suggest that the nucleus is required for the inactivation of the TAT mRNA.
We have tested the ability of polyvinyl alcohol (PVA) to enhance the indoxyl-nitro blue tetrazoli... more We have tested the ability of polyvinyl alcohol (PVA) to enhance the indoxyl-nitro blue tetrazolium alkaline phosphatase color reaction in whole mount in situ hybridizations of early stage quail embryos. Using detection of the myogenic factor qmyoD in hybridizations of 13-14 somite-pair quail embryos as a test system, 10% solutions of 13-23 kDa and 31-50 kDa PVA optimally enhanced the alkaline phosphatase color reaction. With the enhanced detection conditions, we have been able to measure qmyoD expression as early as the 3 somite-pair stage, whereas previously we were unable to detect qmyoD prior to the 10 somite-pair stage. PVA-enhanced detection of somitic qmyoD expression was specific as no corresponding signal was found in control hybridizations with a sense qmyoD probe.
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