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Protein D1 preferentially binds A + T-rich DNA in vitro and is a component of Drosophila melanogaster nucleosomes containing A + T-rich satellite DNA.

Abstract：

:Our previous work [Levinger, L. & Varshavsky, A. (1982) Cell 28, 375-385] has shown that D1, a 50-kilodalton chromosomal protein of Drosophila melanogaster, is specifically associated with isolated nucleosomes that contain a complex A + T-rich satellite DNA with buoyant density of 1.688 g/ml. We show here that D1 is also a component of nucleosomes containing a simple-sequence, pure A + T satellite DNA, buoyant density 1.672 g/ml. Furthermore, using a modification of a protein blotting technique in which proteins are not exposed to dodecyl sulfate denaturation, we have found that D1 preferentially binds to A + T-rich double-stranded DNA in vitro, and it is apparently the only abundant nuclear protein in cultured D. melanogaster cells that possesses this property. Synthetic poly[d(A-T)].poly[d(A-T)] and poly(dA).poly(dT) duplexes effectively compete in vitro with A + T-rich D. melanogaster satellite DNAs for binding to D1, whereas total Escherichia coli DNA is an extremely poor competitor. These findings strongly suggest that D1 is a specific component of A + T-rich, tandemly repeated, heterochromatic regions, which constitute up to 15-20% of the total D. melanogaster genome. Possible functions of D1 protein include compaction of A + T-rich heterochromatin and participation in microtubule-centromere interactions in mitosis. In addition, D1 may prevent nonspecific binding to A + T-rich satellite DNA of other nuclear proteins that have a preference for AT-DNA, such as RNA polymerase or regulatory proteins, and may also participate in the higher-order chromatin organization outside tandemly repetitive regions by binding to nonrandomly positioned stretches of A + T-rich DNA.

journal_name

Proc Natl Acad Sci U S A

journal_title

Proceedings of the National Academy of Sciences of the United States of America

authors

Levinger L,Varshavsky A

doi

10.1073/pnas.79.23.7152

subject

Has Abstract

pub_date

1982-12-01 00:00:00

pages

7152-6

issue

eissn

0027-8424

issn

1091-6490

journal_volume

pub_type

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Protein D1 preferentially binds A + T-rich DNA in vitro and is a component of Drosophila melanogaster nucleosomes containing A + T-rich satellite DNA.