TY - JOUR
T1 - Detection and localization of a chloroplast-encoded HU-like protein that organizes chloroplast nucleoids
AU - Kobayashi, Tamaki
AU - Takahara, Manabu
AU - Miyagishima, Shin Ya
AU - Kuroiwa, Haruko
AU - Sasaki, Narie
AU - Ohta, Niji
AU - Matsuzaki, Motomichi
AU - Kuroiwa, Tsuneyoshi
PY - 2002
Y1 - 2002
N2 - Chloroplast DNA (cpDNA) is packed into discrete structures called chloroplast nucleoids (cp-nucleoids). The structure of cpDNA is thought to be important for its maintenance and regulation. In bacteria and mitochondria, histone-like proteins (such as HU and Abf2, respectively) are abundant and play important roles in DNA organization. However, a primary structural protein has yet to be found in cp-nucleoids. Here, we identified an abundant DNA binding protein from isolated cp-nucleoids of the primitive red alga Cyanidioschyzon merolae. The purified protein had sequence homology with the bacterial histone-like protein HU, and it complemented HU-lacking Escherichia coli mutants. The protein, called HC (histone-like protein of chloroplast), was encoded by a single gene (CmhupA) in the C. merolae chloroplast genome. Using immunofluorescence and immunoelectron microscopy, we demonstrated that HC was distributed uniformly throughout the entire cp-nucleoid. The protein was expressed constitutively throughout the cell and the chloroplast division cycle, and it was able to condense DNA. These results indicate that HC, a bacteria-derived histone-like protein, primarily organizes cpDNA into the nucleoid.
AB - Chloroplast DNA (cpDNA) is packed into discrete structures called chloroplast nucleoids (cp-nucleoids). The structure of cpDNA is thought to be important for its maintenance and regulation. In bacteria and mitochondria, histone-like proteins (such as HU and Abf2, respectively) are abundant and play important roles in DNA organization. However, a primary structural protein has yet to be found in cp-nucleoids. Here, we identified an abundant DNA binding protein from isolated cp-nucleoids of the primitive red alga Cyanidioschyzon merolae. The purified protein had sequence homology with the bacterial histone-like protein HU, and it complemented HU-lacking Escherichia coli mutants. The protein, called HC (histone-like protein of chloroplast), was encoded by a single gene (CmhupA) in the C. merolae chloroplast genome. Using immunofluorescence and immunoelectron microscopy, we demonstrated that HC was distributed uniformly throughout the entire cp-nucleoid. The protein was expressed constitutively throughout the cell and the chloroplast division cycle, and it was able to condense DNA. These results indicate that HC, a bacteria-derived histone-like protein, primarily organizes cpDNA into the nucleoid.
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U2 - 10.1105/tpc.002717
DO - 10.1105/tpc.002717
M3 - Article
C2 - 12119376
AN - SCOPUS:0035984057
SN - 1040-4651
VL - 14
SP - 1579
EP - 1589
JO - Plant Cell
JF - Plant Cell
IS - 7
ER -