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著者 Teerawanichpan,P., Chandrasekharan,M.B., Jiang,Y., Narangajavana,J. and Hall,T.C.
タイトル Characterization of two rice DNA methyltransferase genes and RNAi-mediated reactivation of a silenced transgene in rice callus.
Abstract:
Two genomic clones ( OsMET1-1, AF 462029 and OsMET1-2, TPA BK001405), each encoding a cytosine-5 DNA methyltransferase (MTase), were isolated from rice ( Oryza sativa L.) BAC libraries. OsMET1-1 has an open reading frame of 4,566 nucleotides with 12 exons and 11 introns while OsMET1-2 has an open reading frame of 4,491 nucleotides with 11 exons and 10 introns. Although OsMET1-1 and OsMET1-2 have high sequence similarity overall, they share only 24% identity in exon 1, and intron 3 of OsMET1-1 is absent from OsMET1-2. As for other eukaryotic DNA MTases of the Dnmt1/MET l class, the derived amino acid sequences of OsMET1-1 and OsMET1-2 suggest that they are comprised of two-thirds regulatory domain and one-third catalytic domain. Most functional domains identified for other MTases were present in the rice MET1 sequences. Amino acid sequence comparison indicated high similarity (56-75% identity) of rice MET1 proteins to other plant MET1 sequences but limited similarity (approx. 24% identity) to animal Dnmt1 proteins. Genomic blot and database analysis indicated the presence of a single copy of OsMET1-1 (on chromosome 3) and single copy of OsMET1-2 (on chromosome 7). Ribonuclease protection assays revealed expression of both OsMET1-1 and OsMET1-2 in highly dividing cells, but the steady-state level of OsMET1-2 was 7- to 12-fold higher than that for OsMET1-1 in callus, root and inflorescence. The functional involvement of the rice DNA MTases in gene silencing was investigated using an RNAi strategy. Inverted repeat constructs of either the N- or C-terminal regions of OsMET1-1 were supertransformed into calli derived from a rice line bearing a silenced 35S-uidA-nos transgene. Restoration of uidA expression in the bombarded calli was consistent with the inactivation of maintenance methylation and with previous evidence for the involvement of methylation in silencing of this line.
掲載誌 Planta.
Country USA
刊数 218(3)
ページ 337-349
発刊年 2004
PubMed ID 14513380
PubMed Central ID -
DOI 10.1007/s00425-003-1112-6
URL -
関連情報
遺伝子 MET1A MET1B
INSD AF462029 AY311406 BK001405
系統 野生イネ
コアコレクション
-
突然変異系統(遺伝研 Collection) -
種子不稔系統 -
致死変異体系統 -
組織別発生段階
- 突然変異系統(遺伝子)
-
栽培イネ品種(遺伝研 Collection) -
組織別発生段階 -
/rice/oryzabase