The telobox, a Myb-related telomeric DNA binding motif found in proteins from yeast, plants and human.
The yeast TTAGGG binding factor 1 (Tbf1) was identified and cloned through its ability to interact with vertebrate telomeric repeats in vitro. We show here that a sequence of 60 amino acids located in its C-terminus is critical for DNA binding. This sequence exhibits homologies with Myb repeats and is conserved among five proteins from plants, two of which are known to bind telomeric-related sequences, and two proteins from human, including the telomeric repeat binding factor (TRF) and the predicted C-terminal polypeptide, called orf2, from a yet unknown protein. We demonstrate that the 111 C-terminal residues of TRF and the 64 orf2 residues are able to bind the human telomeric repeats specifically. We propose to call the particular Myb-related motif found in these proteins the 'telobox'. Antibodies directed against the Tbf1 telobox detect two proteins in nuclear and mitotic chromosome extracts from human cell lines. Moreover, both proteins bind specifically to telomeric repeats in vitro. TRF is likely to correspond to one of them. Based on their high affinity for the telomeric repeat, we predict that TRF and orf2 play an important role at human telomeres.
Bilaud
T
T
Laboratoire de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, France.
Koering
C E
CE
Binet-Brasselet
E
E
Ancelin
K
K
Pollice
A
A
Gasser
S M
SM
Gilson
E
E
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism; D010802:Phylogeny; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000378:metabolism; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins; D012045:Regulatory Sequences, Nucleic Acid; D012091:Repetitive Sequences, Nucleic Acid; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D016615:Telomere; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism; D014157:Transcription Factors
D017931:DNA Primers; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C079376:TBF1 protein, S cerevisiae; D015534:Trans-Activators; D014157:Transcription Factors