We isolated and characterized a sequence coding for heat-shock protein 70 (HSP70) of the amphibian Pleurodeles waltl. Results from S1 nuclease protection assays led us to conclude that an hsp70 gene, strictly inducible in somatic cells during heat shock, is constitutively active during oogenesis. By quantitative northern and western blot analysis, we showed… (More)
Fig. 5. Nuclease S1 digestion protection assay of an 850bp [32P] probe consisting of Pw70/3′ (530 bp) + 320bp from the vector. −, negative control with yeast tRNA; +, positive control with sense Pw70/3′ cRNA; P, undigested probe; NL, normal liver; SL, heatshocked liver; ND, normal defolliculated oocytes. SL RNA strongly protects the probe from degradation, while NL RNA does not. Pw70/3′ can therefore be assumed to be a part of a gene strictly inducible in somatic cells. ND RNA protects the probe. Hsp70 RNA is therefore shown to be constitutively expressed in oocytes.