The H1 histone variant of tomato, H1-S, is targeted to the nucleus and accumulates in chromatin in response to water-deficit stress

• Published in: Planta 2000-07, Vol.211 (2), p.173-181
• Main Authors: Scippa, G. Stefania, Griffiths, Allen, Chiatante, Donato, Bray, Elizabeth A.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Antibodies; Biological and medical sciences; Cell Nucleus - physiology; Chromatin; Chromatin - physiology; Cloning, Molecular; Dehydration; Desiccation; DNA; Escherichia coli; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant; Glucuronidase - biosynthesis; Glucuronidase - genetics; Histones; Histones - biosynthesis; Histones - chemistry; Histones - genetics; Kinetics; Leaves; Lycopersicon esculentum - genetics; Lycopersicon esculentum - physiology; Messenger RNA; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Molecular Weight; Plant Leaves - physiology; Plants; Plants, Genetically Modified; Protein Biosynthesis; Recombinant Fusion Proteins; Recombinant Proteins - chemistry; RNA; RNA, Messenger - genetics; RNA, Plant - genetics; Soil water deficit; Time Factors; Transcription, Genetic
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s004250000278

Water deficit has a significant impact on patterns of gene expression. Based on the deduced amino acid sequence, it has been proposed that the drought and abscisic acid-induced gene (his1-s) of tomato (Lycopersicon esculentum Mill.) encodes an H1 histone variant. To study the role of H1-S it is important to understand the expression characteristics of the protein. To identify the his1-s product in vivo the his1-s cDNA was fused to a (His)6 tag and overexpressed in Escherichia coli. The H1-S fusion protein was used to generate an antibody that recognized a protein with an apparent molecular weight of 31 kDa that accumulates in response to water deficit in the whole plant and detached leaves. A time course of his1-s expression showed that protein accumulation is delayed compared to the mRNA accumulation in both the whole plant and detached leaves. Cellular fractionation, immunofluorescence and H1-S::β-glucuronidase fusion analyses in transgenic tissues were used to determine the cellular localization of H1-S. The results showed that H1-S accumulates in nuclei and is associated with chromatin of wilted tomato leaves. The drought- and abscisic acid-induced gene his1-s encodes a linker-histone subtype specifically accumulated in the nuclei and chromatin of tomato leaves subjected to water-deficit conditions. Although the molecular mechanism of H1-S function is still unclear, the expression characteristics of H1-S are consistent with a potential role of this protein in the regulation of gene expression in response to water deficit.