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Transition protein 4 from boar late spermatid nuclei is a topological factor that stimulates DNA‐relaxing activity of topoisomerase I
Author(s) -
Akama Kuniko,
Kondo Miyuki,
Sato Hiroki,
Nakano Minoru
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01649-4
Subject(s) - dna supercoil , spermatid , chromatin , topoisomerase , dna , biology , biochemistry , microbiology and biotechnology , chemistry , dna replication , genetics , sperm
Transition protein 4 (TP4) from boar late spermatid nuclei, having higher affinity for double‐stranded DNA and a local melting activity of DNA, stimulated SV40 DNA‐relaxing activity of eukaryotic topoisomerase I at TP4/DNA molar ratios of 6.6–11. A TP4‐spermidine mixture stimulated the activity of topoisomerase I much more than spermidine alone, but no more than TP4 alone, and poly‐ l ‐arginine did not. These results suggest that TP4 contributes to the chromatin reorganization in the late spermatid nuclei from nucleosomal‐type structure with negatively supercoiled DNA to nucleoprotamine structure with no supercoiled DNA.