Discontinuity of 26 s rRNA in Acanthamoeba castellani

Stevens, A. R.; Pachler, P. F.

doi:10.1016/0022-2836(72)90475-5

Cited by 82 publications

(28 citation statements)

References 24 publications

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“…Split rRNAs have been found in prokaryotes ( Salmonella typhimurium , Burgin et al ., 1990) and in several lower eukaryotes ranging from protozoa ( Euglena gracilis , Rawson et al ., 1971; Acanthamoeba castellani , Stevens and Pachler, 1972; Tetrahymena pyriformis , Eckert et al ., 1978; Trypanosoma cruzi , Castro et al ., 1981; Crithidia fasciculata , Spencer et al ., 1987) to worms ( Schistosoma mansoni , van Keulen et al ., 1991; Trichinella spirallis , Zarlenga and Dame, 1992) and arthropods ( Bombyx mori , Applebaum et al ., 1966; Galleria mellonella , Ishikawa and Newburgh, 1972; Aedes aegypti , Shine and Dalgarno, 1973; Musca carnaria , Lava–Sanchez and Puppo, 1975; Drosophila , Jordan et al ., 1976; Sciara coprophila , Ware et al ., 1985). rRNAs of Chlamydomonas reinhardtii mitochondria (Boer and Gray, 1988) and higher plant chloroplasts (Fujiwara and Ishikawa, 1986) are also fragmented.…”

Section: Discussionmentioning

confidence: 99%

Novel processing in a mammalian nuclear 28S pre-rRNA: tissue-specific elimination of an `intron' bearing a hidden break site

et al. 1999

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Splitting and apparent splicing of ribosomal RNA, both previously unknown in vertebrates, were found in rodents of the genus Ctenomys. Instead of being formed by a single molecule of 4.4 kb, 28S rRNA is split in two molecules of 2.6 and 1.8 kb. A hidden break, mapping within a 106 bp 'intron' located in the D6 divergent region, is expressed in mature ribosomes of liver, lung, heart and spleen, as well as in primary fibroblast cultures. Testis-specific processing eliminates the intron and concomitantly the break site, producing non-split 28S rRNA molecules exclusively in this organ. The intron is flanked by two 9 bp direct repeats, revealing the acquisition by insertion of a novel rRNA processing strategy in the evolution of higher organisms.

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Section: Discussionmentioning

confidence: 99%

Novel processing in a mammalian nuclear 28S pre-rRNA: tissue-specific elimination of an `intron' bearing a hidden break site

et al. 1999

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“…Methods of extraction and analysis were as described previously (Stevens and Pachler, 1972) . Radioactivity in the fractions was determined by liquid scintillation counting after precipitation of the samples with 10% ice-cold TCA and collection on filters (H .…”

Section: Sedimentation Studiesmentioning

confidence: 99%

RNA SYNTHESIS AND TURNOVER DURING DENSITY-INHIBITED GROWTH AND ENCYSTMENT OF ACANTHAMOEBA CASTELLANII

Stevens

Pachler

1973

The Journal of Cell Biology

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Alterations in transcription that precede and accompany encystment (E) of suspension grown A . castellanii have been investigated . Comparative studies were performed on cells undergoing spontaneous E in high density stationary phase cultures or after experimental induction of E at low cell densities by deprivation of nutrients in exponential growth . Onset of growth deceleration at high cell densities was accompanied by an increase in the cellular RNA . The maximum RNA content occurred in cells at stationary phase and subsequently declined with the appearance of cysts in the cultures. On the contrary, the RNA content in cells whose growth was immediately terminated by experimental E induction remained at a constant exponential level through 5 h postinduction and then began to decline shortly before the appearance of cysts. The mature cyst formed in stationary phase cultures and after experimental E induction contained an equivalent amount of RNA (-50% of the exponential value) . Comparison of the kinetics of [ 3 H]uridine incorporation demonstrated that there was an abrupt reduction in the rate of uridine incorporation into RNA with onset of growth deceleration or after growth termination in experimental E induction . The reduced incorporation of uridine into RNA could not be attributed to to a reduced uptake of the isotope by the cells or an altered capacity of the cells to phosphorylate uridine . Uridine continued to be incorporated into RNA at a reduced rate in cells throughout growth deceleration, in stationary phase, and up to 12 h postexperimental induction . Considered together, these results indicate that a buildup in RNA is not necessary for induction of encystment in acanthamoeba . The accumulated RNA in stationary phase cells appears to be due to the greater reduction in the growth rate than in transcription and the absence of RNA turnover in cells during growth deceleration . Initiation of RNA turnover appears to accompany growth termination and induction of E . The results further demonstrate that the regulation of the rate of transcription is closely coordinated with the control of growth and encystment in acanthamoeba .

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“…0.83 x 106-0.88 x 106) (Loening, 1968;Stevens & Pachler, 1972;Cammarano et al, 1975) Loening et al, 1972); S-rRNA of 1 x 106 daltons mass therefore may have arisen by the omission of the final trimming steps in processing, so that the whole '20S' RNA became incorporated in the mature ribosome-. Of greater evolutionary significance is the evidence that the two principal rRNA species of the much evolved Cephalopoda are considerably larger than those of less evolved molluscs such as Gastropoda and Lamellibranchiata, the divergence in rRNA mass between squid and clams (or snails) being more extensive than that existing between the mammals and the Urochordata (Cammarano et al, 1975).…”

Section: Discussionmentioning

confidence: 99%

“…The two major rRNA components of the Dibranchiata appear to have diverged extensively from the corresponding rRNA species of the less evolved Gastropoda and Lamellibranchiata, the L-rRNA of the Decapoda being even larger than that of the warm-blooded animals and the S-rRNA being much larger than that of some Protozoa with unusually large S-rRNA, such as Euglena gracilis (Rawson & Stutz, 1968;Loening, 1968;Cammarano et al, 1975) and Acanthamoeba castellanii (Loening, 1968;Stevens & Pachler, 1972;Cammarano et al, 1975). The L-rRNA of the Cephalopoda is a discontinuous molecule composed of two principal segments held together by a heat-labile structure and appears to comprise two distinct fractions of bihelical segments differing in both length and G + C content.…”

mentioning

confidence: 99%

Physicochemical characterization of the ribosomal RNA species of the Mollusca. Molecular weight, integrity and secondary-structure features of the RNA of the large and small ribosomal subunits

Cammarano¹,

Londei²,

Mazzei³

et al. 1980

Biochemical Journal

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1. The rRNA species of the Cephalopoda Octopus vulgaris and Loligo vulgaris were found to have unexpectedly high sedimentation coefficients and molecular weights. In 0.1 M-NaCI the L-rRNA (RNA from large ribosomal subunit) has the same s2O value as the L-rRNA of the mammals (30.7 S), whereas the S-rRNA (RNA from small ribosomal subunit) sediments at a faster rate (20.1 S) than the S-rRNA of both the mammals and the fungi (Neurospora crassa) (17.5 S). The molecular weights of the L-rRNA were determined by gel electrophoresis in formamide and found to be 1.66 x 106 (Octopus) and 1.89 x 106 (Loligo); the mol.wt. of the S-rRNA of both species is 0.96 x 106, i.e. much larger than that of the mammals (0.65 x 106) and almost coincident with that of the '23S' RNA of the prokaryotes. 2. By contrast, the less evolved Gastropoda and Lamellibranchiata (Murex trunculus and Macrocallista chione) have S-rRNA and L-rRNA species with mol.wts. of 0.65 x 106 and approx.

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Discontinuity of 26 s rRNA in Acanthamoeba castellani

Cited by 82 publications

References 24 publications

Novel processing in a mammalian nuclear 28S pre-rRNA: tissue-specific elimination of an `intron' bearing a hidden break site

Novel processing in a mammalian nuclear 28S pre-rRNA: tissue-specific elimination of an `intron' bearing a hidden break site

RNA SYNTHESIS AND TURNOVER DURING DENSITY-INHIBITED GROWTH AND ENCYSTMENT OF ACANTHAMOEBA CASTELLANII

Physicochemical characterization of the ribosomal RNA species of the Mollusca. Molecular weight, integrity and secondary-structure features of the RNA of the large and small ribosomal subunits

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