ISSN:
1615-6102
Keywords:
Chlamydomonas reinhardtii
;
Chloroplast nucleoidal destruction
;
RNA synthesis
;
UV interference
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The studies on the kinetics of nucleoid destruction reported here showed that destruction of chloroplast nucleoids (ct nucleoids) of male origin began to occur at about 30 minutes after mixing of male (mt−) and female (mt+) gametes. The timing of initiation of the destruction differed among zygotes but usually occurred during 50–120 minutes after mixing. About 10 minutes was required for complete digestion of the ct nucleoids. UV irradiation on young zygotes or addition of an RNA-synthesis inhibitor, actinomycin D, to the incubation medium during the first 0–30 minutes after mixing almost completely inhibited the incorporation of3H uridine into the cell nuclei and the preferential destruction without inhibiting cell nuclear fusion. These results suggest that soon after mating,de novo RNA synthesis is concerned for the preferential destruction of ct nucleoids. To determine in which of the two cell nuclei in the zygotes the RNA is synthesized, each gamete (mt−, mt+) was irradiated with UV and mated with unirradiated gametes of opposite mating type. This treatment of the male gametes had no effect on the incorporation of3H uridine into cell nuclei and the preferential destruction of ct nucleoids but UV irradiation of female gametes almost completely inhibited the incorporation of3H uridine into cell nuclei and the preferential destruction of ct nucleoids. Similar phenomena occurred in other crosses. The UV effect was photoreactivated in about 50% by white light, suggesting that the UV target is DNA. Thus, RNA synthesized in the cell nucleus of female origin soon after mating may be responsible for the preferential destruction of ct nucleoids of male origin
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01297349
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