CLONING OF CDNA-ENCODING A NOVEL MOUSE DNA TOPOISOMERASE-III (TOPO-III-BETA) POSSESSING NEGATIVELY SUPERCOILED DNA RELAXING ACTIVITY, WHOSEMESSAGE IS HIGHLY EXPRESSED IN THE TESTIS

Citation
T. Seki et al., CLONING OF CDNA-ENCODING A NOVEL MOUSE DNA TOPOISOMERASE-III (TOPO-III-BETA) POSSESSING NEGATIVELY SUPERCOILED DNA RELAXING ACTIVITY, WHOSEMESSAGE IS HIGHLY EXPRESSED IN THE TESTIS, The Journal of biological chemistry, 273(44), 1998, pp. 28553-28556
Citations number
19
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology
ISSN journal
0021-9258
Volume
273
Issue
44
Year of publication
1998
Pages
28553 - 28556
Database
ISI
SICI code
0021-9258(1998)273:44<28553:COCANM>2.0.ZU;2-D
Abstract
We cloned cDNA encoding a novel mouse homologue of DNA topoisomerase I II (mTOP3 beta). The nucleotide sequence contains an open reading fram e of 863 amino acids, and the deduced molecular mass of the coded prot ein is 96.9 kDa. The overall sequence of mTOP3 beta has a 48 and 36% i dentity with mouse TOP3 alpha at the nucleotide and amino acid level, respectively. DNA topoisomerase III beta was expressed using a baculov irus expression system and purified. The purified DNA topoisomerase mp had activity to relax negatively supercoiled DNA. Relaxation of super coiled DNA was partial at 37 degrees C and complete relaxation was obs erved at higher temperatures. mTOP3 beta mRNA was strongly expressed i n the testis and relatively strongly in the brain. The levels of TOP3 beta mRNA in the testis increased slightly 14 days and considerably 17 days after birth, when the cells in the pachytene phase bean to appea r and increase.