An increase in the intracellular pH of fertilized eggs of Xenopus laevis is associated with inhibition of protein and DNA syntheses and followed by an arrest of embryonic development.
In many systems, events participating in cell division are controlled by intracellular pH (pHi). In Xenopus eggs, fertilization is accompanied by an increase in pHi which occurs concomitantly with an increase in protein synthesis and a reinitiation of DNA synthesis, leading the embryo to cell division. In this paper, we have shown that increasing pHi of fertilized eggs from 7.8 to 8.2 by using weak bases produced an arrest in embryonic development. Such a change in pHi was accompanied by a severe inhibition of both protein and DNA syntheses. In order to discriminate between a direct effect of pHi and a pH-independent effect of weak bases on these biosyntheses, the situation was studied in vitro. For this purpose, cytoplasmic extracts were used in which weak base addition did not produce any change in pH. Under these conditions, protein synthesis was not inhibited, suggesting that pH is probably one of the events implicated in the regulation of protein synthesis. On the other hand, DNA synthesis was inhibited by weak bases in vitro, without any change in pH intervening.
Grandin
N
N
Laboratoire de Biologie et Génétique du Développement, UA No. 256 CNRS, Université de Rennes I, France.
Charbonneau
M
M
D000818:Animals; D002455:Cell Division; D004247:DNA / Q000096:biosynthesis*; D004261:DNA Replication; D005260:Female; D005306:Fertilization; D006863:Hydrogen-Ion Concentration; D008297:Male; D008715:Methionine / Q000378:metabolism; D008845:Microinjections; D014176:Protein Biosynthesis; D011506:Proteins / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics; D013462:Sulfur Radioisotopes; D013936:Thymidine / Q000378:metabolism; D014982:Xenopus laevis; D015053:Zygote / Q000166:cytology / Q000378:metabolism / Q000502:physiology*
D011506:Proteins; D012333:RNA, Messenger; D013462:Sulfur Radioisotopes; D004247:DNA; D008715:Methionine; D013936:Thymidine