The Fur-like regulatory protein MAP3773c modulates key metabolic pathways in Mycobacterium avium subsp. paratuberculosis under in-vitro iron starvation

Mycobacterium avium subsp. paratuberculosis (MAP) carries MAP3773c, a putative metal regulator, on its genome which is absent in other mycobacteria. Homologues of this gene in enterobacteria have roles in global iron regulation and homeostasis. The role of MAP3773c in regulating intracellular iron in MAP is poorly understood. Functional analysis of DEGs in ?MAP3773c revealed that pantothenate (Pan) biosynthesis, polysaccharide biosynthesis, sugar metabolism and N-acetyltransferase enhanced intracellular survival genes were downregulated at 30 minutes post-iron starvation whereas ATP-binding cassette (ABC) type metal transporters, putative siderophore biosynthesis, arginine and proline metabolism, PPE, PE family and mammalian cell entry (MCE) genes were upregulated at that same time point. Pathway analysis revealed that the MAP3773c knockout has an impairment in Pan and Coenzyme A (CoA) biosynthesis pathways at 30 minutes post-iron starvation suggesting that the absence of those pathways likely affect overall metabolic processes and cellular functions, which have consequences affecting MAP survival and pathogenesis Overall design: A field isolate (K-10) and an in-frame MAP3773c deletion mutant (?MAP3773c) derived from K-10, were exposed to iron restricted conditions for 5, 30, 60, and 90 minutes in six replicates each. Total RNA was extracted at each time point, quality and integrity of the RNA was assessed. Two replicates from each strain and each time points were send for RNA-Sequencing. An iron replete baseline culture was also processed for mRNA extraction and sequencing. A comparison of transcriptional profiles between K-10 and ?MAP3773c were performed.