Plant Molecular Biology

, Volume 36, Issue 5, pp 661–672 | Cite as

Rice proteins that bind single-stranded G-rich telomere DNA

  • Jun Hyun Kim
  • Woo Taek Kim
  • In Kwon Chung


In this work, we have identified and characterized proteins in rice nuclear extracts that specifically bind the single-stranded G-rich telomere sequence. Three types of specific DNA-protein complexes (I, II, and III) were identified by gel retardation assays using synthetic telomere substrates consisting of two or more single-stranded TTTAGGG repeats and rice nuclear extracts. Since each complex has a unique biochemical property and differs in electrophoretic mobility, at least three different proteins interact with the G-rich telomere sequences. These proteins are called rice G-rich telomere binding protein (RGBP) and none of them show binding affinity to double-stranded telomere repeats or single-stranded C-rich sequence. Changing one or two G's to C's in the TTTAGGG repeats abolishes binding activity. RGBPs have a greatly reduced affinity for human and Tetrahymena telomeric sequence and do not efficiently bind the cognate G-rich telomere RNA sequence UUUAGGG. Like other telomere binding proteins, RGBPs are resistant to high salt concentrations. RNase sensitivity of the DNA-protein interactions was tested to investigate whether an RNA component mediates the telomeric DNA-protein interaction. In this assay, we observed a novel complex (complex III) in gel retardation assays which did not alter the mobilities or the band intensities of the two pre-existing complexes (I and II). The complex III, in addition to binding to telomeric sequences, has a binding affinity to rice nuclear RNA, whereas two other complexes have a binding affinity to only single-stranded G-rich telomere DNA. Taken together, these studies suggest that RGBPs are new types of telomere-binding proteins that bind in vitro to single-stranded G-rich telomere DNA in the angiosperms.

rice telomere binding protein single-stranded DNA binding protein telomerase telomere 


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Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Jun Hyun Kim
    • 1
  • Woo Taek Kim
    • 1
  • In Kwon Chung
    • 1
  1. 1.Department of Biology and Bioproducts Research CenterYonsei UniversitySeoulKorea

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