CHARACTERIZATION OF THE DNA-BINDING DOMAIN OF THE AVIAN Y-BOX PROTEIN, CHKYB-2, AND MUTATIONAL ANALYSIS OF ITS SINGLE-STRAND BINDING MOTIF IN THE ROUS-SARCOMA VIRUS ENHANCER
A. Nambiar et al., CHARACTERIZATION OF THE DNA-BINDING DOMAIN OF THE AVIAN Y-BOX PROTEIN, CHKYB-2, AND MUTATIONAL ANALYSIS OF ITS SINGLE-STRAND BINDING MOTIF IN THE ROUS-SARCOMA VIRUS ENHANCER, Journal of virology, 72(2), 1998, pp. 900-909
chkYB-2 is a sequence-specific, single-stranded DNA binding chicken Y-
box protein that promotes Rous sarcoma virus long terminal repeat (RSV
LTR)-driven transcription in avian fibroblasts. The DNA-binding domai
n of chkYB-2 has been mapped by characterizing the DNA binding propel
ties of purified recombinant chkYB-2 mutant polypeptides. The data ind
icate that the invariant cold shock domain (CSD) is necessary but not
sufficient for association with DNA and suggest that another conserved
region, adjacent to the carboxyl boundary of the CSD, plays a role in
high-affinity DNA binding, chkYB-2 binds to a tandem repent of the 5'
-GTACCACC-3' motif on the RSV LTR, Mutational analysis of this recogni
tion sequence revealed the requirement of an essentially unaltered tem
plate for both high-affinity binding by chkYB-2 as well as maximal tra
nscriptional activity of the RSV LTR in vivo. The single-stranded DNA
binding activity of chkYB-2 is augmented by Mg2+. The possible signifi
cance of this finding for transactivation by a single-strand DNA bindi
ng protein is discussed.