RNA-seq analysis of Haloferax volcanii expressing the TIT1 toxin from Halogeometricum borinquense T6SS-like system

This study investigates the transcriptomic response of Haloferax volcanii DS2 upon heterologous expression of TIT1 (Hbor_38900), a DUF4157-containing effector encoded within a type VI secretion system (T6SS)-like gene cluster of Halogeometricum borinquense. TIT1 expression was induced using a tryptophan-inducible promoter in the pTA1926 vector. Total RNA was extracted from H. volcanii cells carrying either the TIT1 expression construct or the empty vector control, each in biological triplicate, after 24 hours of induction with 2 mM tryptophan. Sequencing was performed on the Illumina platform. Differential expression analysis identified 1,350 significantly changed genes (665 upregulated, 685 downregulated). Notably, genes encoding ATP-binding cassette (ABC) transporters involved in uptake of amino acids, biotin, and iron were strongly repressed. These data provide insights into the non-enzymatic mechanism of TIT1, which targets the transcriptional regulator HVO_C0012 and disrupts nutrient acquisition, revealing a novel strategy of inter-archaeal antagonism in hypersaline environments.