Task 1: Post-transcriptional control
TASK 1: POST-TRANSCRIPTIONAL GENE EXPRESSION FROM BACTERIA TO ORGANELLES
(PARTNERS 1, 2, 3, 4, 6)
Modern chloroplasts (cp) and mitochondria (mt) have tiny genomes that only code for a fraction of the factors required for their own gene expression and function. Nevertheless, the organellar machineries for transcription, translation, and mRNA decay have a pronounced prokaryotic nature, because most of the factors involved are the products of ancestral bacterial genes that have been transferred to the nucleus. The nucleus in turn tightly controls the expression of organellar genes by encoding gene-specific factors that bind organellar mRNAs and govern their maturation/stability and translation. In Chlamydomonas reinhardtii, these factors are referred to as M- and T-factors, respectively. In contrast, the Shine-Dalgarno (SD) sequence, which is critical for translation initiation in bacteria, has been lost in most, but not all cp genes.
The principal goal of Task 1 is the comparison of post-transcriptional regulation of gene expression in bacteria (principally Escherichia coli and Bacillus subtilis) and organelles (principally cp in C. reinhardtii) with four main work-packages (WP): A comparison of the mechanisms and regulation of mRNA decay (WP1) and translation (WP2) in cp and bacteria; an investigation of the potential role of small regulatory RNAs in controlling cp gene expression (WP3); a comparison of global networks controlling gene expression at the post-transcriptional level in bacteria and cp (WP4). In addition to these direct comparisons, we made several interesting new discoveries on the post-transcriptional control of gene expression in both bacteria and cp individually. DYNAMO was highly successful in terms of our overall accomplishments for Task 1, with 103 publications in total so far (80 since 2015) and the establishment of new collaborations between the partners that can be directly credited to the project.
Details of our studies can be found here