Perturbation in linker histone content has no effect on the cell cycle but affects the cell size of suspension grown tobacco BY-2 cells

Open and closed: the roles of linker histones in plants and animals

Histones package DNA in all eukaryotes and play key roles in regulating gene expression. Approximately 150 base pairs of DNA wraps around an octamer of core histones to form the nucleosome, the basic unit of chromatin. Linker histones compact chromatin further by binding to and neutralizing the charge of the DNA between nucleosomes. It is well established that chromatin packing is regulated by a complex pattern of posttranslational modifications (PTMs) to core histones, but linker histone function is less well understood. In this review, we describe the current understanding of the many roles that linker histones play in cellular processes, including gene regulation, cell division, and development, while putting the linker histone in the context of other nuclear proteins. Although intriguing roles for plant linker histones are beginning to emerge, much of our current understanding comes from work in animal systems. Many unanswered questions remain and additional work is required to fully elucidate the complex processes mediated by linker histones in plants.

Ectopic expression of the maize chromosomal HMGB1 protein causes defects in root development of tobacco seedlings

Chromatin-associated high mobility group (HMG) proteins of the HMGB family are versatile architectural factors assisting various DNA-dependent processes such as transcription and recombination. Here, transgenic tobacco lines were generated that ectopically express the maize HMGB1 protein, as detected by immunoblot analyses. The shoot morphology of HMGB1 expressing plants does not differ from that of control plants. By contrast, tobacco seedlings expressing HMGB1 are impaired in the growth of the primary root, relative to control plants. The reduced primary root length is correlated with the accumulation of small cells in the cell division zone (but not in the elongation zone) of the roots of transgenic plants. This "short-root" phenotype is specific for HMGB1, as is not observed with HMGB4 expressing plants, and it is transient in that it is restricted to young seedlings ( Collapse

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MESH Headings

• Cell Division
• Chromosomes, Plant/chemistry
• HMGB1 Protein/biosynthesis
• HMGB1 Protein/genetics
• HMGB1 Protein/metabolism
• HMGB1 Protein/physiology
• Microscopy, Fluorescence
• Plant Roots/growth & development
• Plant Roots/ultrastructure
• Plants, Genetically Modified/genetics
• Plants, Genetically Modified/growth & development
• Plants, Genetically Modified/metabolism
• Seedlings/growth & development
• Seedlings/metabolism
• Nicotiana/genetics
• Nicotiana/growth & development
• Nicotiana/metabolism
• Zea mays/chemistry
• Zea mays/genetics

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Affiliation(s)

Jacek Lichota Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark
Christoph Ritt
Klaus D Grasser

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