Reference "Sequence-specific DNA recognition by the Myb-like domain of plant telomeric protein RTBP1"

Reference ID

5205

Title

Sequence-specific DNA recognition by the Myb-like domain of plant telomeric protein RTBP1

Source

The Journal of biological chemistry, 2000, vol. 275, pp. 24208-24214

Authors (6)

Yu-E-Y	Kim-S-E
Kim-J-H	Ko-J-H
Cho-M-H	Chung-I-K

Abstract

We have identified a rice gene encoding a DNA-binding protein that specifically
recognizes the telomeric repeat sequence TTTAGGG found in plants. This gene,
which we refer to as RTBP1 (rice telomere-binding protein 1), encodes a
polypeptide with a predicted molecular mass of 70 kDa. RTBP1 is ubiquitously
expressed in various organs and binds DNA with two or more duplex TTTAGGG
repeats. The predicted protein sequence includes a single domain at the C
terminus with extensive homology to Myb-like DNA binding motif. The Myb-like
domain of RTBP1 is very closely related to that of other telomere-binding
proteins, including TRF1, TRF2, Taz1p, and Tbf1p, indicating that DNA-binding
domains of telomere-binding proteins are well conserved among evolutionarily
distant species. To obtain precise information on the sequence of the DNA
binding site recognized by RTBP1, we analyzed the sequence-specific binding
properties of the isolated Myb-like domain of RTBP1. The isolated Myb-like
domain was capable of sequence-specific DNA binding as a homodimer. Gel
retardation analysis with a series of mutated telomere probes revealed that the
internal GGGTTT sequence in the two- telomere repeats is critical for binding of
Myb-like domain of RTBP1, which is consistent with the model of the TRF1.DNA
complex showing that base-specific contacts are made within the sequence GGGTTA.
To the best of our knowledge, RTBP1 is the first cloned gene in which the
product is able to bind double-stranded telomeric DNA in plants. Because the Myb-
like domain appears to be a significant motif for a large class of proteins that
bind the duplex telomeric DNA, RTBP1 may play important roles in plant telomere
function in vivo.