Tertiary structure of the soluble surface proteins of Paramecium

Reisner, A. H.; Rowe, Janet; Sleigh, Robert W

doi:10.1021/bi00839a061

Cited by 45 publications

(17 citation statements)

References 20 publications

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“…Figure la shows the i-antigens for 11 serotypes of P. tetraurelia stock 51. We used the positions and molecular weights of serotypes A and B (molecular weights, 301,500 and 259,000, respectively) (19) as standards and calculated the molecular weights of the other antigens from their positions on the gels relative to A and B (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Structure and expression of genes for surface proteins in Paramecium.

et al. 1983

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Surface proteins from 11 antigenic types of Paramecium tetraurelia vary in molecular weight from 251,000 to 308,000. The size of a series of polyadenylated RNAs obtained from these types were correlated with the sizes of the proteins and judged to be the mRNAs for the proteins. The mRNAs were used to identify genomic DNA clones containing complementary sequences. The gene for antigen A was present in one copy per genome, and the data suggest that extensive introns were absent. When restriction enzyme digests of DNA from cultures of paramecia with active and inactive genes were probed with portions of the cloned genes, no evidence for rearrangements or changes in gene dosage was found.

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Section: Resultsmentioning

confidence: 99%

Structure and expression of genes for surface proteins in Paramecium.

et al. 1983

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“…By using the sizes of i-ags given by Reisner et al. (26) as standards (301,500 daltons for 51A, 259,000for B, and 271,000 for D), the molecular sizes can be calculated on the assumption that the distance traveled is linearly related to the logarithm of the molecular size. The sizes were estimated to be A, 300,000; H, 288,000; D, 280,000; E, 270,000; B, 253,000; and C, 250,000 daltons.…”

Section: Methodsmentioning

confidence: 99%

mRNAs for the immobilization antigens of Paramecium

Preer

Rudman

1981

Proc. Natl. Acad. Sci. U.S.A.

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Immobilization antigens of stock 51 of Paramecium tetraurelia were subjected to electrophoresis in NaDodSO4/ polyacrylamide gels. Type A is estimated to have a molecular size of 300,000 daltons; H is estimated to be 288,000, D to be 280,000, E to be 270,000, B to be 253,000, and C to be 250,000. Poly(A)+RNAs have been isolated from cells producing these antigens and subjected to electrophoresis in methylmercury gels. A major band is found to vary in mobility with antigenic type: Its position in preparations derived from paramecia synthesizing antigen A indicates a size of 8400 nucleotide residues; its position from paramecia synthesizing other antigens indicate H, 8200; D, 7900; E, 7500; B, 7600; and C, 7000. Because ofthe sizes and quantities of these RNAs, it is argued that they probably represent the mRNAs for the immobilization antigens. It is concluded that each immobilization antigen probably consists of a single polypeptide and that only one major serotype-determining mRNA is present in each antigenically different paramecium.Differences in gene expression that can be classified as simple environmental modifications are well known. Often, however, differences in gene expression show cellular inheritance; subclones that have alternative phenotypes may arise and reproduce true to type, even though all are under the same environmental conditions. The molecular mechanisms responsible for several instances ofinherited differences in gene expression have recently been discovered. Gene rearrangements have proved to be the basis for all cases. They include mating types in yeast (1), antigenic variation in Salmonella (2) and trypanosomes (3-5), and the production ofantibodies (6). Transposable elements in a variety of organisms (7-9) can also lead to modification of gene action.Since all ofthese cases involve changes in DNA, it is not surprising that they all are relatively stable and are not, as far as we know, directed by environmental stimuli. The production of antibodies may be an exception. Although antigens trigger the formation of specific antibodies, they do so by stimulating growth and synthesis. They select cells that have specific rearrangements, but there is no evidence that they induce rearrangements. Moreover, order in the sequence of changes exhibited by classes ofantibodies and in the succession ofantigenic types in trypanosomes does not necessarily imply specific induction. Nevertheless, a role for the environment in the induction of antibodies may exist, for the rearrangements occur in specific cells at specific times in development, suggesting that unknown inducing conditions may exist in those cells.Differences in the expression of genes determining immobilization proteins or i antigens (i-ags) of Paramecium are in some respects anomalous. They are heritable under certain environmental conditions and some show preferred sequences of change from one state to the other. Brown (10) has suggested that they too will prove to be due to gene rearrangments. However, they are unlike the cases d...

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“…Solution of Jennings' fourth order equation allows us to estimate molecular dimensions on the assumption that ellipsoids of revolution are an appropriate approximation to the proteins' shapes. In the case of the P. aurelia proteins, it has been established that they are in fact oblate-like (Reisner, Rowe and Sleigh, 1969), and we find it interesting that the axis of rotation for the T. brucei proteins, if they be oblate-like, is the same length as that for the Paramecium antigens. It is this thickness of 15-16 A which suggested previously that the P. aurelia proteins may be quasi-double-biresidue leaflets in which a double layer of hydrophobic core amino acid residues is completely surrounded by a hydrophilic amino acid residue coat.…”

Section: -18mentioning

confidence: 59%

“…Amino acid analyses and physical parameters for six of the soluble surface proteins from P. aurelia have been reported previously (Jones, 1965;Reisner, Rowe and Sleigh, 1969). Data for the surface antigens from T. brucei were obtained from Cross (1975), while amino acid compositional data for a representative set of 208 proteins have been compiled by Reeck (1970).…”

Section: Datamentioning

confidence: 99%

“…From time to time, however, some have suggested that such a relevance might exist because of certain observed similarities in antigenic variation (Inoki et al, 1960 and previous papers in that series; Beale, 1974). On the other hand, the recent work of Cross (1975), in which he isolated and characterized six soluble surface proteins from Trypanosoma brucei, allows us to compare these antigenic substances with the soluble surface proteins isolated from P. aureiia (Jones, 1965;Reisner, Rowe and Sleigh, 1969).…”

Section: Introductionmentioning

confidence: 98%

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DETERMINATION OF THE RELATEDNESS OF THE SOLUBLE SURFACE PROTEINS OF TRYPANOSOMA BRUCEI AND PARAMECIUM AURELIA

Reisner

Westwood

1977

Aust J Exp Biol Med

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Summary The soluble surface proteins isolated by Cross (1975) from Trypanosoma brucei are compared to those which occur on Paramecium aurelia. Calculations based on the amino acid residue data and the molecular weights of these surface antigens indicate that there is a considerable degree of similarity between the T. brucei and the P. aurelia proteins, and that in neither case can simple mutation be responsible for the differences of molecules within each family of antigens. The analyses are consistent with the suggestion that the P. aurelia system can serve as a model for the phenomenon of phase transformation (relapse syndrome) which occurs in trypanosomiasis.

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Tertiary structure of the soluble surface proteins of Paramecium

Cited by 45 publications

References 20 publications

Structure and expression of genes for surface proteins in Paramecium.

Structure and expression of genes for surface proteins in Paramecium.

mRNAs for the immobilization antigens of Paramecium

DETERMINATION OF THE RELATEDNESS OF THE SOLUBLE SURFACE PROTEINS OF TRYPANOSOMA BRUCEI AND PARAMECIUM AURELIA

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