Participation of DNA structure on sperm chromatin organization

Citation
G. Fuentes-mascorro et al., Participation of DNA structure on sperm chromatin organization, ARCH ANDROL, 45(1), 2000, pp. 61-71
Citations number
41
Language
INGLESE
art.tipo
Article
Categorie Soggetti
da verificare
Journal title
ARCHIVES OF ANDROLOGY
ISSN journal
0148-5016 → ACNP
Volume
45
Issue
1
Year of publication
2000
Pages
61 - 71
Database
ISI
SICI code
0148-5016(200007/08)45:1<61:PODSOS>2.0.ZU;2-5
Abstract
The in vitro interaction between purified bovine liver and sperm DNA with s omatic histones, to form nucleosomes, and with bovine and salmon protamines were studied. DNAse or microccocal nuclease digestion of liver DNA-histone reassociated chromatin produced the expected polynucleosome type of fragme nts. Electrophoretic patterns of digested sperm-DNA nucleosomes were differ ent. Micrococcal nuclease digestion produced mainly fragments smaller than 100 bp and some nucleosome-type particles. Under DNAse activity most of the products were smaller than 100 bp, indicating an increased susceptibility of the sperm DNA-histone complexes to the hydrolytic activity of both nucle ases, particularly toward DNAse I. This differential susceptibility was con firmed by sucrose gradient spectrophotometric analysis. Acridine orange (AO ) staining of histone-DNA reassociated nucleosomes showed significant diffe rences in fluorescence intensity, sperm DNA-histone complexes being almost twice as fluorescent as liver DNA-histone complexes. On the contrary, liver DNA/protamine complexes stained with AO were consistently more fluorescent than sperm DNA-protamine complexes. Finally, no differences in either fluo rescence intensity or spectra were observed when liver and sperm DNA were s tained with AO after interaction with salmon protamines. The data suggest t hat sperm DNA has important structural characteristics that differentiates it from somatic DNA. These differences seem to be species specific and must surely play an important role on the determination of the dramatic sequenc e of that participates sperm chromatin organization.