Occurrence of heat-dissociable ribosomal RNA in insects: the presence of three polynucleotide chains in 26 S RNA from cultured Aedes aegypti cells.

Autor(es): Shine J; Dalgarno L

Resumo: When RNA extracted from a mixture of cultured mosquito (Aedes aegypti) and hamster (BHK) cells is heated at 60 °C for five minutes the 26 S mosquito RNA but not the 28 S BHK RNA is converted to 18 S products. These products are not separable from each other or from pre-existent 18 S RNA on 2.4% acrylamide gels and have molecular weights near 0.7 × 106. The large ribosomal RNA from insects belonging to ten different orders shows a similar conversion, although this property is absent in two species of aphid. A. aegypti 26 S RNA dissociates over a narrow temperature range. The reaction equilibrium favours dissociation and is dependent on ionic strength, showing a 6 deg. C change in Tm' (the temperature of 50% dissociation) with tenfold change in salt concentration. Although the Tm of 26 S RNA from Drosophila melanogaster and A. aegypti is markedly different, reflecting the difference in base composition, the Tm' of the two RNA species was virtually the same. High molecular weight ribosomal RNA from Escherichia coli, BHK cells and A. aegypti cells was terminally labelled with [3H]isonicotinic acid hydrazide. The specific activities of the large RNA species show the presence of one, two and three polynucleotide chains in 23 S, 28 S and 26 S RNA, respectively. A. aegypti 26 S RNA contains a small, heat-dissociable "IRNA" similar in relative amount and mobility to that found in BHK cells.

Imprenta: Journal of Molecular Biology, v. 75, n. 1, p. 57-72, 1973

Identificador do objeto digital: 10.1016/0022-2836(73)90528-7

Descritores: Aedes aegypti - Cell ; Aedes aegypti - RNA

Data de publicação: 1973