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. 1988 Feb;7(2):455–463. doi: 10.1002/j.1460-2075.1988.tb02833.x

Polygene transcripts are precursors to calmodulin mRNAs in trypanosomes.

C Tschudi 1, E Ullu 1
PMCID: PMC454342  PMID: 3366120

Abstract

In African trypanosomes, calmodulin is encoded by a small family of tandemly repeated genes consisting of three to four units. We show that all the members of the calmodulin cluster of Trypanosoma brucei gambiense are expressed. In addition to mature mRNAs, steady-state RNA contains a small percentage of polygene transcripts which comprise at least two and probably all calmodulin genes. The 5' ends of a portion of these molecules appear to be indistinguishable from those of mature calmodulin mRNAs. Polygene transcripts are not polyadenylated and have discrete ends which map in the intergenic regions downstream from the polyadenylation sites. Using biotinylated hybridization probes and selection of the hybrids on streptavidin-agarose, we further show that calmodulin polygene transcripts are the most abundant RNA species detected in pulse-labelled RNA of cultured procyclic trypanosomes. Our data strongly imply that polygene transcripts are authentic precursors to mature calmodulin mRNAs.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Auffray C., Rougeon F. Purification of mouse immunoglobulin heavy-chain messenger RNAs from total myeloma tumor RNA. Eur J Biochem. 1980 Jun;107(2):303–314. doi: 10.1111/j.1432-1033.1980.tb06030.x. [DOI] [PubMed] [Google Scholar]
  2. Benton W. D., Davis R. W. Screening lambdagt recombinant clones by hybridization to single plaques in situ. Science. 1977 Apr 8;196(4286):180–182. doi: 10.1126/science.322279. [DOI] [PubMed] [Google Scholar]
  3. Boothroyd J. C. Antigenic variation in African trypanosomes. Annu Rev Microbiol. 1985;39:475–502. doi: 10.1146/annurev.mi.39.100185.002355. [DOI] [PubMed] [Google Scholar]
  4. Borst P. Discontinuous transcription and antigenic variation in trypanosomes. Annu Rev Biochem. 1986;55:701–732. doi: 10.1146/annurev.bi.55.070186.003413. [DOI] [PubMed] [Google Scholar]
  5. Campbell D. A., Thornton D. A., Boothroyd J. C. Apparent discontinuous transcription of Trypanosoma brucei variant surface antigen genes. 1984 Sep 27-Oct 3Nature. 311(5984):350–355. doi: 10.1038/311350a0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Clayton C. E. Structure and regulated expression of genes encoding fructose biphosphate aldolase in Trypanosoma brucei. EMBO J. 1985 Nov;4(11):2997–3003. doi: 10.1002/j.1460-2075.1985.tb04035.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Contreras R., Fiers W. Initiation of transcription by RNA polymerase II in permeable, SV40-infected or noninfected, CVI cells; evidence for multiple promoters of SV40 late transcription. Nucleic Acids Res. 1981 Jan 24;9(2):215–236. doi: 10.1093/nar/9.2.215. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Cunningham I. New culture medium for maintenance of tsetse tissues and growth of trypanosomatids. J Protozool. 1977 May;24(2):325–329. doi: 10.1111/j.1550-7408.1977.tb00987.x. [DOI] [PubMed] [Google Scholar]
  9. De Lange T., Liu A. Y., Van der Ploeg L. H., Borst P., Tromp M. C., Van Boom J. H. Tandem repetition of the 5' mini-exon of variant surface glycoprotein genes: a multiple promoter for VSG gene transcription? Cell. 1983 Oct;34(3):891–900. doi: 10.1016/0092-8674(83)90546-9. [DOI] [PubMed] [Google Scholar]
  10. De Lange T., Michels P. A., Veerman H. J., Cornelissen A. W., Borst P. Many trypanosome messenger RNAs share a common 5' terminal sequence. Nucleic Acids Res. 1984 May 11;12(9):3777–3790. doi: 10.1093/nar/12.9.3777. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Gonzalez A., Lerner T. J., Huecas M., Sosa-Pineda B., Nogueira N., Lizardi P. M. Apparent generation of a segmented mRNA from two separate tandem gene families in Trypanosoma cruzi. Nucleic Acids Res. 1985 Aug 26;13(16):5789–5804. doi: 10.1093/nar/13.16.5789. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Grummt I., Kuhn A., Bartsch I., Rosenbauer H. A transcription terminator located upstream of the mouse rDNA initiation site affects rRNA synthesis. Cell. 1986 Dec 26;47(6):901–911. doi: 10.1016/0092-8674(86)90805-6. [DOI] [PubMed] [Google Scholar]
  13. Henderson S., Sollner-Webb B. A transcriptional terminator is a novel element of the promoter of the mouse ribosomal RNA gene. Cell. 1986 Dec 26;47(6):891–900. doi: 10.1016/0092-8674(86)90804-4. [DOI] [PubMed] [Google Scholar]
  14. Hernandez N. Formation of the 3' end of U1 snRNA is directed by a conserved sequence located downstream of the coding region. EMBO J. 1985 Jul;4(7):1827–1837. doi: 10.1002/j.1460-2075.1985.tb03857.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Kooter J. M., De Lange T., Borst P. Discontinuous synthesis of mRNA in trypanosomes. EMBO J. 1984 Oct;3(10):2387–2392. doi: 10.1002/j.1460-2075.1984.tb02144.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. McStay B., Reeder R. H. A termination site for Xenopus RNA polymerase I also acts as an element of an adjacent promoter. Cell. 1986 Dec 26;47(6):913–920. doi: 10.1016/0092-8674(86)90806-8. [DOI] [PubMed] [Google Scholar]
  17. Melton D. A., Krieg P. A., Rebagliati M. R., Maniatis T., Zinn K., Green M. R. Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter. Nucleic Acids Res. 1984 Sep 25;12(18):7035–7056. doi: 10.1093/nar/12.18.7035. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Merritt S. C., Tschudi C., Konigsberg W. H., Richards F. F. Reverse transcription of trypanosome variable antigen mRNAs initiated by a specific oligonucleotide primer. Proc Natl Acad Sci U S A. 1983 Mar;80(6):1536–1540. doi: 10.1073/pnas.80.6.1536. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Michels P. A., Poliszczak A., Osinga K. A., Misset O., Van Beeumen J., Wierenga R. K., Borst P., Opperdoes F. R. Two tandemly linked identical genes code for the glycosomal glyceraldehyde-phosphate dehydrogenase in Trypanosoma brucei. EMBO J. 1986 May;5(5):1049–1056. doi: 10.1002/j.1460-2075.1986.tb04321.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Michiels F., Matthyssens G., Kronenberger P., Pays E., Dero B., Van Assel S., Darville M., Carvador A., Steinert M., Hamers R. Gene activation and re-expression of a Trypanosoma brucei variant surface glycoprotein. EMBO J. 1983;2(7):1185–1192. doi: 10.1002/j.1460-2075.1983.tb01565.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Milhausen M., Nelson R. G., Sather S., Selkirk M., Agabian N. Identification of a small RNA containing the trypanosome spliced leader: a donor of shared 5' sequences of trypanosomatid mRNAs? Cell. 1984 Oct;38(3):721–729. doi: 10.1016/0092-8674(84)90267-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Miller M. R., Castellot J. J., Jr, Pardee A. B. A permeable animal cell preparation for studying macromolecular synthesis. DNA synthesis and the role of deoxyribonucleotides in S phase initiation. Biochemistry. 1978 Mar 21;17(6):1073–1080. doi: 10.1021/bi00599a021. [DOI] [PubMed] [Google Scholar]
  23. Murphy W. J., Watkins K. P., Agabian N. Identification of a novel Y branch structure as an intermediate in trypanosome mRNA processing: evidence for trans splicing. Cell. 1986 Nov 21;47(4):517–525. doi: 10.1016/0092-8674(86)90616-1. [DOI] [PubMed] [Google Scholar]
  24. Murray N. E., Brammar W. J., Murray K. Lambdoid phages that simplify the recovery of in vitro recombinants. Mol Gen Genet. 1977 Jan 7;150(1):53–61. doi: 10.1007/BF02425325. [DOI] [PubMed] [Google Scholar]
  25. Nelson R. G., Parsons M., Barr P. J., Stuart K., Selkirk M., Agabian N. Sequences homologous to the variant antigen mRNA spliced leader are located in tandem repeats and variable orphons in trypanosoma brucei. Cell. 1983 Oct;34(3):901–909. doi: 10.1016/0092-8674(83)90547-0. [DOI] [PubMed] [Google Scholar]
  26. Parsons M., Nelson R. G., Watkins K. P., Agabian N. Trypanosome mRNAs share a common 5' spliced leader sequence. Cell. 1984 Aug;38(1):309–316. doi: 10.1016/0092-8674(84)90552-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Proudfoot N. J., Brownlee G. G. Sequence at the 3' end of globin mRNA shows homology with immunoglobulin light chain mRNA. Nature. 1974 Nov 29;252(5482):359–362. doi: 10.1038/252359a0. [DOI] [PubMed] [Google Scholar]
  28. Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Sutton R. E., Boothroyd J. C. Evidence for trans splicing in trypanosomes. Cell. 1986 Nov 21;47(4):527–535. doi: 10.1016/0092-8674(86)90617-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Thomashow L. S., Milhausen M., Rutter W. J., Agabian N. Tubulin genes are tandemly linked and clustered in the genome of trypanosoma brucei. Cell. 1983 Jan;32(1):35–43. doi: 10.1016/0092-8674(83)90494-4. [DOI] [PubMed] [Google Scholar]
  31. Tschudi C., Young A. S., Ruben L., Patton C. L., Richards F. F. Calmodulin genes in trypanosomes are tandemly repeated and produce multiple mRNAs with a common 5' leader sequence. Proc Natl Acad Sci U S A. 1985 Jun;82(12):3998–4002. doi: 10.1073/pnas.82.12.3998. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Van der Ploeg L. H., Liu A. Y., Michels P. A., De Lange T., Borst P., Majumder H. K., Weber H., Veeneman G. H., Van Boom J. RNA splicing is required to make the messenger RNA for a variant surface antigen in trypanosomes. Nucleic Acids Res. 1982 Jun 25;10(12):3591–3604. doi: 10.1093/nar/10.12.3591. [DOI] [PMC free article] [PubMed] [Google Scholar]

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