We describe a deoxyribonuclease activity from nuclear protein extracts of cultured Aedes albopictus mosquito cells. The nuclease cleaved linear and circular double-stranded DNA, first generating 3′ OH single-stranded nicks followed by second strand cleavage, but had little or no exonucleolytic activity. Detection of this activity was optimal at pH 7.1, in the presence of a divalent cation (Mg2+, Ca2+, Mn2+, Ba2+). In the presence of Mg2+, Zn2+, Hg2+ and Cu2+ inhibited activity, sulfhydryl reagents and ATP had no effect. At physiological temperatures (18-35°C), linear double-stranded DNA probes were preferentially cleaved near sites containing 3-6 consecutive deoxyadenine/thymine base pairs. Results from salt dependency and drug inhibition studies, combined with inspection of DNA sequence, suggested that DNA structure is among the parameters that determine preferred cleavage sites.
|Original language||English (US)|
|Number of pages||16|
|Journal||Comparative Biochemistry and Physiology -- Part B: Biochemistry and|
|State||Published - Jan 1995|
- DNA structure
- Divalent cation