Change in nuclear potassium electrochemical activity and puffing of potassium-sensitive salivary chromosome regions during Chironomus development.

P Wuhrmann, H Ineichen, U Riesen-Willi, M Lezzi

Index: Proc. Natl. Acad. Sci. U. S. A. 76 , 806, (1979)

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Abstract

Changes in nuclear K+ electrochemical activity and total nuclear K+ content in salivary glands of Chironomus tentans were measured with ion-selective microelectrodes based on valinomycin and with flameless atomic absorption spectrometry, respectively. The K+ activity increased by a factor of 2.6 and the total K+, by a factor of 1.5 as oligopausing larvae developed into prepupae. The extent of decondensation (puffing) of K+-sensitive regions in the polytene chromosomes underwent a parallel increase during this developmental event. In vitro culture of glands from oligopausing larvae resulted in similar changes with respect to nuclear K+ activity and puffing.