ISSN:
1617-4623
Keywords:
Dictyostelium
;
Cysteine proteinases
;
Development
;
Regulation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary We analysed the expression of two genes encoding two different cysteine proteinases which show a high degree of homology and are regulated differentially during Dictyostelium discoideum development. While absent from growing vegetative cells, the two specific messengers RNAs appear at an early stage of development but accumulate in the polysomes at different later stages of development. The message coding for cysteine proteinase I reaches its maximum level after the aggregative period while cysteine proteinase II mRNA reaches its maximum during the culmination stage. At these times they represent 1% and 0.7%, respectively, of cellular mRNA and belong to the most abundant class of mRNAs. No accumulation of the two messages elsewhere than in the polyribosomes was observed in the cytoplasm of the cells, whatever the stage of development analysed. Results of analysis of the nuclear levels of RNA complementary to the two genes are in agreement with the relative transcription rates determined by in vitro transcription of nuclei isolated at different stages. The combined results of these measurements demonstrate that the expression of the cysteine proteinase I and II genes is mainly under transcriptional control. However, the difference between the RNA synthetic rate in the nucleus and the accumulation of the mRNA in the cytoplasm, indicates an additional post-transcriptional regulation for the cysteine proteinase II gene.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00333976
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