engleski

Heat stress significantly stabilizes BPM1 protein in Arabidopsis thaliana seedlings

MATH-BTB proteins are comprised of two domains, MATH (Meprin and TRAF Homology) and BTB (Bric- A-Brac, Tramtrack, Broad Complex). While the MATH domain recognizes specific substrates, BTB domain binds Cullin 3 (CUL3) of the E3 ubiquitin ligase complex which ubiquitinates and thereby designates target proteins for proteasomal degradation. The MATH-BTB gene family is represented by six members in the Arabidopsis genome (AtBPM1-6). AtBTB proteins interact with members of at least three families of transcription factors (R2R3 MYB family, ethylene response factor/Apetala2 and class I homeobox-leucine zipper transcription factors) which play important roles during plant flowering, seed development and abiotic stress response. Here, transgenic A. thaliana plants with overexpression of GFP-tagged BPM1 were successfully regenerated and analyzed, exhibiting early flowering phenotype and resistance to ABA. Despite high overexpression rate, recombinant BPM1 protein was unstable under control conditions. The stability of BPM1 protein was analyzed after treatment of transgenic seedlings in conditions of salt and osmotic stress (150 mM NaCl or 300 mM mannitol), darkness, elevated temperatures, and upon heat stress. Seedlings were collected for whole soluble protein extraction and anti-GFP monoclonal antibody was used to blot transgenic GFP-tagged proteins. Darkness and salt stress induced degradation of GFP-BPM1, as opposed to heat treatment which caused significant accumulation of GFP-BPM1. Improved stabilization of transgenic GFP-BPM1 in conditions of elevated temperature could indicate the physiological role of AtBPM1 in response to heat stress.

Arabidopsis, BPM1, heat stress, immunodetection

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