Poly(A)+ RNA synthesis in germinating pollen ofNicotiana tabacum L |
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Authors: | J Süss J Tupý |
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Institution: | (1) Institute of Experimental Botany, Czechoslovak Academy of Sciences, Flemingovo nám. 2, 160 00 Praha 6, Czechoslovakia |
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Abstract: | Poly(A)+RNA is synthesized during the first hours of pollen germination and is rapidly incorporated into polysomal structures. After
a 2-h pulse with uracil-14C, 42% of the transcribed fraction of polysomal RNA is polyadenylated. Following 4 h of germination the amount of the newly-made
poly(A)+RNA decreases steadily at the rate of about 14% per h, whereas that of rapidly-labelled poly(A)−RNA continues to grow. Beginning 1 h of cultivation the ratio of poly(A)−/poly(A)+RNA increases exponentially. Similarly as in non-polyadenylated mRNA the main portion of the synthesized polysomal poly(A)+RNA sediments at a rate of 4 to 14 S and its mean size decreases slightly with the time of labelling. RNA isolated from nuclei
and cell wall containing pollen tube fraction differed from the polysomal one in higher apeoific radioactivity and the polyadenylated
RNA exhibited higher size distribution. The comparison of the results with earlier observations suggests the involvement of
poly(A)in mRNA translation in pollen tubes. |
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