Circadian and senescence-enhanced expression of a tobacco cysteine protease gene.
A cDNA clone encoding a cysteine protease was isolated from a tobacco cDNA library, utilizing as a probe a PCR fragment obtained from degenerated primers based on the conserved sequences of plant cysteine protease genes. A putative protein encoded by the clone NTCP-23 had an amino acid sequence with significant similarities to those of plant senescence-associated cysteine proteases and mammalian cathepsin H. Northern blot analysis showed that NTCP-23 mRNA is expressed in all organs and the mRNA and protein expression is enhanced during natural senescence. We propose that NTCP-23 is responsible for amino acid remobilization especially in senescencing leaves. Furthermore, it was found that the mRNA expression follows a circadian rhythm and is reduced by continuous darkness, wounding and hypersensitive reaction (HR). NTCP-23 is the first cysteine protease whose mRNA expression has been shown to be temporarily reduced by wounding.
Ueda
T
T
National Institute of Agrobiological Resources, Tsukuba, Ibaraki, Japan. uechu@abr.affrc.go.jp
Seo
S
S
Ohashi
Y
Y
Hashimoto
J
J
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D002940:Circadian Rhythm / Q000502:physiology*; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000821:virology; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics; D010947:Plants, Toxic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013314:Stress, Mechanical; D014018:Tissue Distribution; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D014027:Tobacco Mosaic Virus / Q000254:growth & development
D018076:DNA, Complementary; D012333:RNA, Messenger; D018749:RNA, Plant; D003546:Cysteine Endopeptidases