title: Characterization of a novel otubain-like protease with deubiquitination activity from Nosema bombycis (Microsporidia).
abstract: Otubains are a recently identified family of deubiquitinating enzymes (DUBs). They are involved in diverse biological processes including protein degradation, signal transduction, and cell immune response. Several microsporidian genomes have been published in the last decade; however, little is known about the otubain-like protease in these widely-spread obligate intracellular parasites. Here, we characterized a 25 kDa otubain-like protease (NbOTU1) from the microsporidian Nosema bombycis, the pathogen causing pebrine disease in the economically important insect Bombyx mori. Sequence analysis showed that this protein contained a conserved catalytic triad of otubains composed of aspartate, cysteine, and histidine residues. The expression of Nbotu1 began on day 3 postinfection as determined by the RT-PCR method. Immunofluorescence analysis indicated that NbOTU1 is localized on the spore wall of N. bombycis. The subcellular localization of the NbOTU1 was further detected with immunoelectron microscopy, which showed that NbOTU1 is localized at the regions around endospore wall and plasma membrane. Deubiquitination analysis confirmed that the recombinant NbOTU1 possessed deubiquitination activity in vitro. Taken together, a novel microsporidian otubain-like protease NbOTU1 was partially characterized in N. bombycis, demonstrating its subcellular location and deubiquitination activity. This study provided a basic reference for further dissecting the function of otubains in microsporidia.
authors.affiliation: State Key Laboratory of Silkworm genome Biology, Southwest University, Chongqing, 400716, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiaoqun
authors.initials: X
authors.lastname: Dang
authors.forename: Bo
authors.initials: B
authors.lastname: Luo
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Li
authors.forename: Mengxian
authors.initials: M
authors.lastname: Long
authors.forename: Tian
authors.initials: T
authors.lastname: Li
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Guoqing
authors.initials: G
authors.lastname: Pan
authors.forename: Zeyang
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002473:Cell Wall; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D015966:Gene Expression Regulation, Fungal / Q000502:physiology; D016818:Nosema / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases