Three distinct sub-nuclear populations of HMG-I protein of different properties revealed by co-localization image analysis. - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Journal of Cell Science Année : 1998

Three distinct sub-nuclear populations of HMG-I protein of different properties revealed by co-localization image analysis.

Résumé

We have studied the nuclear distribution of the non-histone HMG-I protein by indirect immunofluorescence in several human and murine somatic cell lines and in growing mouse oocytes. We show that HMG-I, a high mobility-group protein which interacts in vitro with the minor groove of AT-rich B-DNA, is found exclusively in the nucleus and that this localization corresponds to a complex distribution. By comparing the HMG-I-dependent fluorescence signal with the chromatin density determined by Hoechst 33342 or propidium iodide staining, we present evidence for the existence of three HMG-I sub-populations whose contribution to the total fluorescence can be determined using a newly developed quantitative co-localization image analysis program: foci that correspond to regions of heterochromatin, intense dots located within decondensed chromatin, and a more diffuse component extending throughout the nucleoplasm. In addition, we show that these sub-populations differ in their sensitivity to nuclease digestion and in vivo displacement by the minor-groove binder Hoechst 33342. Finally, double immunolabeling of RNA polymerase II-dependent transcription and HMG-I shows that the intense dots are not correlated with sites of high transcriptional activity. We discuss the possibility that these three sub-populations reflect distinct and separable biological functions of the HMG-I protein.
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Dates et versions

hal-02610659 , version 1 (17-05-2020)

Identifiants

  • HAL Id : hal-02610659 , version 1
  • PUBMED : 9811569

Citer

C Amirand, A Viari, J Ballini, Human Rezaei, Nathalie Beaujean, et al.. Three distinct sub-nuclear populations of HMG-I protein of different properties revealed by co-localization image analysis.. Journal of Cell Science, 1998, 111 ( Pt 23), pp.3551-3561. ⟨hal-02610659⟩
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