Novel insights into the plant histone code: lessons from ORC1.
Gene expression control depends on the combinatorial presence of various posttranslational modifications of the N-terminal tail of histones, among which acetylation and methylation of lysine residues are the most conspicuous. Effector proteins have been identified that recognize specific histone modifications and transduce the information of the histone code into different degrees of chromatin compaction in either facultative or constitutive heterochromatin. In addition, they also impinge on transcriptional control, either activation or repression, of euchromatic genes. However, a large variety of effector proteins lead to different gene expression readouts. This is complicated by accumulating evidence showing that the consequences of various histone modifications differ among animals and plants. Given the conservation of histone marks, and histone modification enzymes, this has evolutionary implications as to how they are interpreted differently in different organisms. One example that illustrates such diversity of the histone code is the large subunit of the origin recognition complex, ORC1. In plants, but not in yeast and animal cells, ORC1 functions as a transcriptional activator of a subset of target genes and is a plant homeodomain (PHD)-containing protein that binds to histone H3K4me3 residues.
Sanchez
María de la Paz
Mde L
Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, Madrid 28049, Spain.
Gutierrez
Crisanto
C
D000107:Acetylation; D000818:Animals; D002843:Chromatin / Q000378:metabolism; D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant; D006657:Histones / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology; D051738:Origin Recognition Complex / Q000235:genetics / Q000502:physiology*; D015533:Transcriptional Activation
D002843:Chromatin; D006657:Histones; D018398:Homeodomain Proteins; D051738:Origin Recognition Complex