A drought-stress-inducible histone gene in Arabidopsis thaliana is a member of a distinct class of plant linker histone variants.
We have isolated and characterized a gene, His1-3, encoding a structurally divergent linker histone in Arabidopsis thaliana. Southern and northern hybridization data indicate that A. thaliana expresses three single-copy linker histone genes, each encoding a structurally distinct variant. H1-3 is a considerably smaller protein (167 amino acids with a mass of 19.0 kDa) than any other described linker histone from higher eukaryotes. We examined the expression of His1-3 at the RNA and protein levels and found that it is induced specifically by water stress. In contrast, expression of His1-1, His1-2 and His4 appear unaffected by water stress. Furthermore, the primary structure of the protein possesses distinct characteristics that are shared with another drought-inducible linker histone, H1-D, isolated from Lycopersicon pennellii. Based on structural characteristics of the deduced protein and its inducible expression, we hypothesize that H1-3 and H1-D are linker histone variants that have specialized roles in the structure and function of plant chromatin and therefore they can be considered to be members of a unique subclass of plant histones. Immunoblotting with an antibody produced against a short polypeptide in the conserved domain of this subtype indicates that similar proteins may exist in other plants.
Ascenzi
R
R
Department of Plant Biology, University of Minnesota, St. Paul 55108, USA.
Gantt
J S
JS
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D001483:Base Sequence; D002843:Chromatin / Q000737:chemistry; D003001:Cloning, Molecular; D004190:Disasters; D018506:Gene Expression Regulation, Plant; D006657:Histones / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D018517:Plant Roots / Q000235:genetics; D018520:Plant Shoots / Q000235:genetics; D011487:Protein Conformation; D012333:RNA, Messenger / Q000096:biosynthesis; D018749:RNA, Plant / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014867:Water / Q000378:metabolism
D002843:Chromatin; D006657:Histones; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D014867:Water