Regulation of biosynthesis and intracellular localization of rice and tobacco homologues of nucleosome assembly protein 1.
The nucleosome assembly protein 1 (NAP1) is considered to be a conserved histone chaperone, facilitating the assembly of nucleosomes in all eukaryotes. However, studies in yeast and animal cells also indicated that NAP1 proteins have diverse functions likely independent of nucleosome-assembly activity. Here, we describe the isolation and characterization of cDNAs encoding NAP1-like proteins from the monocotyledon rice ( Oryza sativa L.) and the dicotyledon tobacco ( Nicotiana tabacum L.). Northern-blot analysis demonstrated that the two rice NAP1-like genes are predominantly expressed in stem tissues such as root and shoot apical meristems as well as in young flowers. During the cell cycle, all four tobacco NAP1-like genes are highly expressed, with one of them showing a slightly increased expression at the G1/S transition. These results are consistent with a role for plant NAP1-like proteins in cell division. In vitro binding assays revealed that different NAP1-like proteins bind, with distinct relative binding strengths, to different classes of histone. Intracellular localization analyses showed that some NAP1-like proteins could be targeted into the nucleus whereas others are exclusively cytoplasm-localized. It is thus likely that different plant NAP1-like proteins have distinct functions in vivo. Plant NAP1-like proteins were observed to concentrate around the metaphase plate and in the phragmoplast, suggesting a role in mitotic events and cytokinesis.
Dong
Aiwu
A
Institut de Biologie Moléculaire des Plantes du CNRS, Université Louis Pasteur de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg Cédex, France.
Zhu
Yan
Y
Yu
Yu
Y
Cao
Kaiming
K
Sun
Chongrong
C
Shen
Wen-Hui
WH
D000595:Amino Acid Sequence; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D018797:Cell Cycle Proteins; D002460:Cell Line; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000378:metabolism; D018547:Plant Stems / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000166:cytology / Q000235:genetics* / Q000378:metabolism
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D008164:Luminescent Proteins; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D010940:Plant Proteins; D020033:Protein Isoforms; D011506:Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins