Regulation of expression of trehalose-6-phosphate synthase during cold shock in Arthrobacter strain A3.

Trehalose is a chemical chaperone known to protect a variety of organisms against cold stress. Members of the genus Arthrobacter, which belongs to the Actinomycetales group, exhibit strong resistance to stress conditions, but exactly how trehalose synthesis is regulated in conditions of cold stress is still unknown. Here, we report that Arthrobacter strain A3, which was isolated from the alpine permafrost, has only two trehalose synthesis pathways (OtsA/B and TreS), while other Arthrobacter spp. have three. Mutants and immunoblot analyses indicate that trehalose is mainly synthesized via OtsA at low temperatures in Arthrobacter strain A3. Therefore, we have focused on the regulation of OtsA expression during cold shock. The results indicated that both low temperature and accumulation of trehalose can inhibit OtsA expression. The elongation factor Tu, which binds to OtsA, stabilizes the expression of OtsA in the cold.