Changes in intranuclear chromatin architecture induce bipolar nuclear localization of histone variant H1T2 in male haploid spermatids.
Spermiogenesis entails a major biochemical and morphological restructuring of the germ cell packing the DNA into the condensed spermatid nucleus. H1T2 is a histone H1 variant selectively and transiently expressed in male haploid germ cells during spermiogenesis that specifically localizes to a chromatin domain at the apical pole under the acrosome. We explored the mechanisms determining polar localization of H1T2 in spermatids. In acrosome-deficient round spermatids of hrb -/- and gopc -/- mice, H1T2 localization is not altered, indicating that proper acrosome development is not required for specifying nuclear polarity. In contrast, in late round spermatids from trf2 -/- or hmgb2 -/- mice, a bipolar H1T2 localization was observed revealing that polarity is modified by loss of proteins specifying chromatin architecture. Our results show that intranuclear chromatin organization is critical for correct polar localization of H1T2 and that H1T2 can be a useful molecular marker revealing chromatin disorganization in spermatids.
Catena
Raffaella
R
Institut de Génétique et de Biologie Molécularie et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch Cedex, France.
Ronfani
Lorenza
L
Sassone-Corsi
Paolo
P
Davidson
Irwin
I
D021581:Active Transport, Cell Nucleus / Q000235:genetics; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005819:Genetic Markers; D014644:Genetic Variation; D006238:Haploidy; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000235:genetics; D013087:Spermatids / Q000378:metabolism*
D002843:Chromatin; D004268:DNA-Binding Proteins; D005819:Genetic Markers; C503502:H1T2 protein, mouse; D009687:Nuclear Proteins