STUDY OF ROLE OF THE ARABIDOPSIS DUAL-TARGETING RNA POLYMERASE RPOTmp IN MITOCHONDRIA AND CHLOROPLASTS

Original title

ИЗУЧЕНИЕ РОЛИ РНК-ПОЛИМЕРАЗЫ ДВОЙНОЙ НАПРАВЛЕННОСТИ RPOTmp В МИТОХОНДРИЯХ И ХЛОРОПЛАСТАХ

Authors

Tarasenko V.I., Garnik E.Yu., Katyshev A.I., Belkov V.I., Yakovleva T.V., Chernikova V.V., Konstantinov Yu.M., Koulintchenko M.V.

Contact information

Siberian Institute of Plant Physiology and Biochemistry SB RAS, Russia, e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.

Pages

133-135

DOI

10.31255/978-5-94797-318-1-133-135

Abstract

The transcription of organellar genes in Arabidopsis is performed by three NEP (nuclear-encoded RNA polymerases), RPOTm, RPOTmp and RPOTp. In mitochondria of plants, RPOTm performs the main function, while RPOTp, along with the RNA polymerase of chloroplast coding (PEP), is involved in plastid transcription. RNA polymerase RPOTmp is a protein that is localized in both mitochondria and chloroplasts, however, the main functions of the NEP are associated with mitochondria. The Arabidopsis insertion mutant rpotmp is characterized by retarded growth and development, altered leaves morphology, changed expression of a number of nuclear and mitochondrial genes. The aim of the work is to study role of RPOTmp in expression of organelle genes and potential impact of this RNA polymerase on functions of other NEP and in regulation of early plant development. Previously, we obtained lines expressing RPOTmp targeting either into mitochondria (Col-M) or into chloroplasts (Col-P) using the transformation of the wild-type Arabidopsis plants. An analysis of a number of the transgene insertions in obtained lines with RPOTmp overexpression revealed that the identified variability in a number of integrated copies of the transgene has no significant effect neither on expression of recombinant RPOTmp, nor on manifestation of any distinctive features in particular Arabidopsis lines. The obtained data show that the overexpression of recombinant RPOTmp leads to suppression of the native gene transcription in all investigated transgenic plants. Correlation between the phenotypic manifestation in these plants and the decrease in transcript level of native RPOTmp was not also detected. The only promoter for which the specificity of recognition by RNA polymerase RPOTmp is convincingly shown in chloroplasts is a PC promoter of the rrn16-operon. The transcription activity from this promoter is observed mainly at extremely early stages of plant development, when seeds swell and germinate. The transcription level from the rpotmp-specific chloroplast PC-promoter of the rrn16 operon in all lines with complementation (Tmp-M and Tmp-P) and overexpression (Col-M and Col-P) of this NEP in mitochondria and chloroplasts was analyzed. The increase of transcription from the PC promoter was revealed only in lines expressing RPOTmp in chloroplasts. Activation of transcription from the PC promoter of the rrn16 operon indicates the special role of RPOTmp in regulation of expression of chloroplast genes at the early stages of seed germination.