Skip to main content
PMC home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1987 Jul;84(14):4924–4928. doi: 10.1073/pnas.84.14.4924

An extrachromosomal form of the Mu transposons of maize.

V Sundaresan, M Freeling
PMCID: PMC305219  PMID: 3037528

Abstract

Maize lines known as Robertson's Mutator (Mu) lines generate unstable recessive mutations at high frequencies. These lines carry actively transposing copies of the transposons (Tn) Mu1 and Mu1.7. TnMu1 and TnMu1.7 are approximately 1400 and 1700 base pairs long, respectively, and they have 210-base-pair terminal inverted repeats. We report here extrachromosomal forms of TnMu1 and TnMu1.7. The extrachromosomal Mu1 and Mu1.7 molecules are resistant to alkaline denaturation and to proteinase treatment and have circular restriction maps; therefore, they are probably covalently closed circular DNA. Further, we show that their occurrence is correlated with Mu activity, so they are probably generated during Mu transposition as transposition intermediates or as products of Mu excision. When the total extrachromosomal supercoiled DNA from immature male flowers of a Mu line was examined by electron microscopy, the Mu transposons appeared to constitute a significant fraction of the extrachromosomal DNA circles in Mu lines.

Full text

PDF
4924

Images in this article

4925Image
on p.4925
4925Image
on p.4925
4926Image
on p.4926
4927Image
on p.4927
4927Image
on p.4927

Selected References

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

  1. Alleman M., Freeling M. The Mu transposable elements of maize: evidence for transposition and copy number regulation during development. Genetics. 1986 Jan;112(1):107–119. doi: 10.1093/genetics/112.1.107. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Barker R. F., Thompson D. V., Talbot D. R., Swanson J., Bennetzen J. L. Nucleotide sequence of the maize transposable element Mul. Nucleic Acids Res. 1984 Aug 10;12(15):5955–5967. doi: 10.1093/nar/12.15.5955. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bender J., Kleckner N. Genetic evidence that Tn10 transposes by a nonreplicative mechanism. Cell. 1986 Jun 20;45(6):801–815. doi: 10.1016/0092-8674(86)90555-6. [DOI] [PubMed] [Google Scholar]
  4. Bennetzen J. L., Swanson J., Taylor W. C., Freeling M. DNA insertion in the first intron of maize Adh1 affects message levels: cloning of progenitor and mutant Adh1 alleles. Proc Natl Acad Sci U S A. 1984 Jul;81(13):4125–4128. doi: 10.1073/pnas.81.13.4125. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Cappello J., Handelsman K., Lodish H. F. Sequence of Dictyostelium DIRS-1: an apparent retrotransposon with inverted terminal repeats and an internal circle junction sequence. Cell. 1985 Nov;43(1):105–115. doi: 10.1016/0092-8674(85)90016-9. [DOI] [PubMed] [Google Scholar]
  6. Chandler V. L., Walbot V. DNA modification of a maize transposable element correlates with loss of activity. Proc Natl Acad Sci U S A. 1986 Mar;83(6):1767–1771. doi: 10.1073/pnas.83.6.1767. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Flavell A. J., Brierley C. The termini of extrachromosomal linear copia elements. Nucleic Acids Res. 1986 May 12;14(9):3659–3669. doi: 10.1093/nar/14.9.3659. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Flavell A. J., Ish-Horowicz D. Extrachromosomal circular copies of the eukaryotic transposable element copia in cultured Drosophila cells. Nature. 1981 Aug 13;292(5824):591–595. doi: 10.1038/292591a0. [DOI] [PubMed] [Google Scholar]
  9. Johns M. A., Mottinger J., Freeling M. A low copy number, copia-like transposon in maize. EMBO J. 1985 May;4(5):1093–1101. doi: 10.1002/j.1460-2075.1985.tb03745.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. 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]
  11. Mossie K. G., Young M. W., Varmus H. E. Extrachromosomal DNA forms of copia-like transposable elements, F elements and middle repetitive DNA sequences in Drosophila melanogaster. Variation in cultured cells and embryos. J Mol Biol. 1985 Mar 5;182(1):31–43. doi: 10.1016/0022-2836(85)90025-7. [DOI] [PubMed] [Google Scholar]
  12. Murray M. G., Thompson W. F. Rapid isolation of high molecular weight plant DNA. Nucleic Acids Res. 1980 Oct 10;8(19):4321–4325. doi: 10.1093/nar/8.19.4321. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Robertson D. S. Genetic studies on the loss of mu mutator activity in maize. Genetics. 1986 Jul;113(3):765–773. doi: 10.1093/genetics/113.3.765. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Robertson D. S. The timing of mu activity in maize. Genetics. 1980 Apr;94(4):969–978. doi: 10.1093/genetics/94.4.969. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Rose A. M., Snutch T. P. Isolation of the closed circular form of the transposable element Tc1 in Caenorhabditis elegans. Nature. 1984 Oct 4;311(5985):485–486. doi: 10.1038/311485a0. [DOI] [PubMed] [Google Scholar]
  16. Ruan K., Emmons S. W. Extrachromosomal copies of transposon Tc1 in the nematode Caenorhabditis elegans. Proc Natl Acad Sci U S A. 1984 Jul;81(13):4018–4022. doi: 10.1073/pnas.81.13.4018. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Saedler H., Nevers P. Transposition in plants: a molecular model. EMBO J. 1985 Mar;4(3):585–590. doi: 10.1002/j.1460-2075.1985.tb03670.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Shapiro J. A. Molecular model for the transposition and replication of bacteriophage Mu and other transposable elements. Proc Natl Acad Sci U S A. 1979 Apr;76(4):1933–1937. doi: 10.1073/pnas.76.4.1933. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Southern E. M. Detection of specific sequences among DNA fragments separated by gel electrophoresis. J Mol Biol. 1975 Nov 5;98(3):503–517. doi: 10.1016/s0022-2836(75)80083-0. [DOI] [PubMed] [Google Scholar]
  20. Stanfield S., Helinski D. R. Small circular DNA in Drosophila melanogaster. Cell. 1976 Oct;9(2):333–345. doi: 10.1016/0092-8674(76)90123-9. [DOI] [PubMed] [Google Scholar]
  21. Werr W., Frommer W. B., Maas C., Starlinger P. Structure of the sucrose synthase gene on chromosome 9 of Zea mays L. EMBO J. 1985 Jun;4(6):1373–1380. doi: 10.1002/j.1460-2075.1985.tb03789.x. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES