Characterization of DNA polymerase delta from a higher plant, rice (Oryza sativa L.).
DNA polymerase delta (pol delta), which is comprised of at least two essential subunits, is an important enzyme involved in DNA replication and repair. We have cloned and characterized both the catalytic and small subunits of pol delta from rice (Oryza sativa L. cv. Nipponbare). The open reading frames of OsPoldelta1 and delta2 encoded a predicted product of 1105 amino acid residues with a molecular weight of 124 kDa for OsPoldelta1, and of 429 residues with a molecular weight of 48 kDa for OsPoldelta2. Northern blotting analysis indicated that OsPoldelta1 and delta2 transcripts were expressed strongly in proliferating tissues such as shoot apical meristem. The expression patterns of both subunits in the organs were slightly different. Therefore, we analyzed the spatial distribution pattern of OsPoldelta1 transcripts by in situ hybridization. In the shoot apex, OsPoldelta1 mRNA was abundant in the shoot apical meristem. In the roots, the OsPoldelta1 transcript accumulated at high levels in the root apical meristem. In mature leaves, OsPoldelta1 was induced after UV irradiation, but OsPoldelta2 was not. The amounts of the OsPoldelta1 and delta2 mRNAs in the rice cells changed rapidly during cell proliferation. These results indicated that the levels of OsPoldelta expression are markedly correlated with cell proliferation, and that some of OsPoldelta might have special roles in the leaves.
Uchiyama
Yukinobu
Y
Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
Hatanaka
Masami
M
Kimura
Seisuke
S
Ishibashi
Toyotaka
T
Ueda
Tadamasa
T
Sakakibara
Yoshikiyo
Y
Matsumoto
Takashi
T
Furukawa
Tomoyuki
T
Hashimoto
Junji
J
Sakaguchi
Kengo
K
D020134:Catalytic Domain / Q000235:genetics; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003001:Cloning, Molecular; D004258:DNA Polymerase III / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000235:genetics; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology / Q000235:genetics*; D010802:Phylogeny; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013395:Sucrose / Q000494:pharmacology
D018076:DNA, Complementary; D007527:Isoenzymes; D012333:RNA, Messenger; D013395:Sucrose; D004258:DNA Polymerase III