The N-terminal region of the Arabidopsis thaliana LaRP6C protein contributes to structural stability




Roberts, Julia E.

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The La-related proteins (LaRPs) are a superfamily of RNA-binding proteins that are distinguished by a core RNA binding domain called the “La Module”. This family is highly conserved across eukaryotes and exerts diverse functions in RNA processing and function. The genetic model vascular plant, Arabidopsis thaliana (At), has three paralogs of LaRP6, denoted “A”, “B”, and “C”. Of these paralogs, AtLaRP6B and AtLaRP6C are more closely related to each other as both have an N-terminal sequence motif known to associate with other RNA binding proteins, the “PAM2w” motif. Previous work evaluated the RNA binding activity of the isolated AtLaRP6C La Module. Recent work on vertebrate LaRP4A suggests that N-terminal PAM2 motifs are important for higher-order assembly of regulatory complexes. We have generated a set of recombinant constructs deleting the C-terminal domain (CTD) to test the role of both the N-terminal region (NTR) and PAM2w motif in RNA binding activity. These protein variants are stably expressed and have been highly purified for use in electrophoretic mobility shift assays (EMSAs) to measure RNA binding activity. Although binding does occur, quantifiable data has not been obtained by this methodology. However, the effect of these domains on melting temperature (Tm), a stability parameter, have been obtained. Deletion of the PAM2w does not affect these parameters, whereas deletion of the CTD greatly impacts these values.



LaRP, RNA binding proteins, Thermofluor, SYPRO Orange, Arabidopsis thaliana, RNA


Roberts, J. E. (2020). <i>The N-terminal region of the Arabidopsis thaliana LaRP6C protein contributes to structural stability</i> (Unpublished thesis). Texas State University, San Marcos, Texas.


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