BRIEF REPORT |
Correspondence to: Alberto M. Martelli, Dipartimento di Morfologia Umana, Università di Trieste, via Manzoni 16, I-34138 Trieste, Italy.
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Summary |
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The intranuclear distribution of HMGI/Y proteins was analyzed by immunofluorescent staining in several cell lines using a polyclonal antibody that stained a fibrogranular network. In actively growing 3T3 fibroblasts, HMGI/Y proteins were mainly localized to heterochromatin masses, whereas in quiescent cells they were more diffusely distributed. Double labeling experiments showed a co-localization of HMGI/Y with DNA topoisomerase II. These results are in agreement with previously published biochemical data and indicate a possible involvement of HMGI/Y proteins in several nuclear functions, including chromatin organization and gene expression. (J Histochem Cytochem 46: 863864, 1998)
Key Words: HMGI/Y proteins, 3T3 fibroblasts, immunofluorescent staining, heterochromatin
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Introduction |
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High-mobility group (HMG) PROTEINS I/Y are part of a subset of nonhistone proteins that also includes HMGI-C, and these three polypeptides are referred to as HMGI (
Moreover, it has been shown that transforming viruses are no longer able to transform rat thyroid cells if the cells also transcribe an anti-sense message for HMGI-C ( co-localize along the scaffold of mitotic chromosomes, we analyzed by double immunostaining and CLSM whether this type of association was present in the interphase nucleus of HeLa cells. As shown in Figure 1j, almost all of the immunofluorescent signal due to HMGI/Y (Figure 1h, red) co-localized with that due to topoisomerase II
(Figure 1i, green). Topoisomerase II
was immunostained by monoclonal antibody Ki-S1 (BoehringerMannheim; Mannheim, Germany).
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In conclusion, we believe that our data are in agreement with previous findings (obtained by biochemical and molecular biology techniques) indicating an involvement of HMGI/Y in several key nuclear functions (
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Acknowledgments |
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Supported by Associazione Italiana per la Ricerca sul Cancro (A.I.R.C.) 1996 grants to AMM and VG, and from Italian MURST 40% and 60% grants to Università di Trieste.
Received for publication October 14, 1997; accepted March 3, 1998.
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