Open AccessHistone H1 overexpressed to high level in tobacco affects certain developmental programs but has limited effect on basal cellular functions.
Author(s) -
Marta Prymakowska-Bosak,
Marcin R. Przewloka,
J Iwkiewicz,
S Egierszdorff,
Mieczysław Kuraś,
Nicole Chaubet,
Claude Gigot,
Steven Spiker,
Andrzej Jerzmanowski
Publication year - 1996
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.93.19.10250
Subject(s) - chromatin , biology , histone , chromatin remodeling , microbiology and biotechnology , repressor , multicellular organism , epigenetics , histone h1 , phenotype , transgene , transcription factor , arabidopsis , nucleosome , gene , regulation of gene expression , genetics , mutant
Histone H1, a major structural component of chromatin fiber, is believed to act as a general repressor of transcription. To investigate in vivo the role of this protein in transcription regulation during development of a multicellular organism, we made transgenic tobacco plants that overexpress the gene for Arabidopsis histone H1. In all plants that overexpressed H1 the total H1-to-DNA ratio in chromatin increased 2.3-2.8 times compared with the physiological level. This was accompanied by 50-100% decrease of native tobacco H1. The phenotypic changes in H1-overexpressing plants ranged from mild to severe perturbations in morphological appearance and flowering. No correlation was observed between the extent of phenotypic change and the variation in the amount of overexpressed H1 or the presence or absence of the native tobacco H1. However, the severe phenotypic changes were correlated with early occurrence during plant growth of cells with abnormally heterochromatinized nuclei. Such cells occurred considerably later in plants with milder changes. Surprisingly, the ability of cells with highly heterochromatinized nuclei to fulfill basic physiological functions, including differentiation, was not markedly hampered. The results support the suggestion that chromatin structural changes dependent on H1 stoichiometry and on the profile of major H1 variants have limited regulatory effect on the activity of genes that control basal cellular functions. However, the H1-mediated chromatin changes can be of much greater importance for the regulation of genes involved in control of specific developmental programs.