A role of the -35 element in the initiation of transcription at psbA promoter in tobacco plastids.
Most plastid promoters recognized by bacteria-like plastid RNA polymerase (PEP) are similar to E. coli sigma(70)-type promoters comprising "-35" and "-10" elements. Among them, psbA promoter is unique in bearing additional elements between the conserved -35 and -10 elements. The psbA promoter activity is differentially maintained in the mature chloroplasts where the activity of most PEP promoters declines. Previously, we identified two types of PEP activities in wheat seedlings [Satoh et al. (1999) Plant J. 18: 407]; PEP present in the mature chloroplasts of the leaf tip (tip-type PEP) can initiate transcription from the -35-destructed psbA promoter, but the -35 element is essential for transcription by PEP present in immature chloroplasts of the leaf base (base-type PEP). To reveal which type of PEP functions in various types of plastids in tobacco, we analyzed the tobacco psbA promoter by means of a transplastomic approach. The promoter core context (-42 to +9) was sufficient for developmental regulation of the psbA promoter activity. The -35 promoter element was important for transcription initiation at the psbA promoter in all types of plastids, including chloroplasts in mature leaves, leucoplasts in roots, etioplasts in etiolated cotyledons. The conclusion is that the PEP bearing a promoter preference, similar to the wheat base-type PEP, functions dominantly in tobacco chloroplasts.
Hayashi
Keiko
K
Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto, 606-8501 Japan.
Shiina
Takashi
T
Ishii
Nao
N
Iwai
Kayou
K
Ishizaki
Yoko
Y
Morikawa
Kazuya
K
Toyoshima
Yoshinori
Y
D001483:Base Sequence; D002736:Chloroplasts / Q000235:genetics*; D008027:Light; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics* / Q000528:radiation effects; D045332:Photosystem II Protein Complex; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D014026:Nicotiana / Q000235:genetics*; D014158:Transcription, Genetic / Q000528:radiation effects
D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex