P. Vargaweisz et al., PREFERENTIAL BINDING OF HISTONE H1 TO 4-WAY HELICAL JUNCTION DNA, The Journal of biological chemistry, 268(28), 1993, pp. 20699-20700
Histone H1 is a major chromatin protein, which stabilizes the nucleoso
me, has an essential role in organizing nucleosomes into higher order
structures, and may have a role as a repressor of transcription (van H
olde, K. E. (1989) Chromatin, Springer Publishing Co., New York). Here
we show that H1 forms a defined complex with a synthetic four-way jun
ction of DNA strands even in the presence of an excess of linear nonsp
ecific competitor DNA. The four-way junction also competes efficiently
against two duplex DNA molecules, which together have the same sequen
ce information as the four-way junction molecule. Another major chroma
tin protein, high mobility group protein 1, also binds four-way juncti
on structures specifically (Bianchi, M. E., Beltrame, M., and Paonessa
, G. (1989) Science 243, 1056-1059), and this similar behavior may ind
icate a related function of these proteins. Our finding may suggest th
at four-way DNA junction is a structural equivalent to the main H1 bin
ding site in the nucleosome: a crossover of double helical DNA at the
point where the DNA enters and exits the nucleosome (Allan, J., Hartma
n, P. G., Crane-Robinson, C., and Aviles, F. X. (1980) Nature 288, 675
-679).