title: Evolutionary conservation of C-terminal domains of primary sigma(70)-type transcription factors between plants and bacteria.
abstract: Three different cDNAs coding for putative plant plastid sigma(70)-type transcription initiation factors have recently been cloned and sequenced from Arabidopsis thaliana. We have analyzed the evolutionary conservation of function(s) of the N-terminal and C-terminal halves of these three sigma factors by in vitro transcription studies using heterologous transcription systems and by complementation assays using Escherichia coli thermosensitive rpoD mutants. Our results indicate differences and similarities of the three plant factors and their prokaryotic ancestors. The functions of the N-terminal parts of the plant sigma factors are considerably different from the function of the N-terminal part of the principal sigma(70) factor of E. coli. On the other hand, the C-terminal parts have kept at least two characteristics when compared with their prokaryotic ancestors: 1) they can distinguish between different promoter structures, and 2) one of them is capable of fully complementing E. coli rpoD mutants, i.e. recognizing all essential E. coli promoters that are used by the E. coli principal sigma(70) factor. This shows for the first time in vivo a strong evolutionary conservation of cis- and trans-acting elements between the prokaryotic and the plant plastid transcriptional machinery.
authors.affiliation: Laboratoire de Génétique Moléculaire des Plantes, "Plastes et Differenciation Cellulaire," Université Joseph Fourier and CNRS, B. P. 53X, F-38041 Grenoble, France.
authors.forename: M A
authors.initials: MA
authors.lastname: Hakimi
authors.forename: I
authors.initials: I
authors.lastname: Privat
authors.forename: J G
authors.initials: JG
authors.lastname: Valay
authors.forename: S
authors.initials: S
authors.lastname: Lerbs-Mache
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D017124:Conserved Sequence; D018076:DNA, Complementary; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D019143:Evolution, Molecular; D005816:Genetic Complementation Test; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010944:Plants / Q000201:enzymology / Q000235:genetics*; D011401:Promoter Regions, Genetic; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012808:Sigma Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D012808:Sigma Factor; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases