Ssn6 Interacts with Polar Tube Protein 2 and Transcriptional Repressor for RNA Polymerase II: Insight into Its Involvement in the Biological Process of Microsporidium Nosema bombycis .

is a representative species of Microsporidia, and is the pathogen that causes pebrine disease in silkworms. In the process of infection, the polar tube of is injected into the host cells. During proliferation, recruits the mitochondria of host cells. The general transcriptional corepressor Ssn6 contains six tetratricopeptide repeats (TPR) and undertakes various important functions. In this study, we isolated and characterized of the microsporidium . The gene contains a complete ORF of 1182 bp in length that encodes a 393 amino acid polypeptide. Indirect immunofluorescence assay showed that the Ssn6 protein was mainly distributed in the cytoplasm and nucleus at the proliferative phase of . We revealed the interaction of Nbssn6 with polar tube protein 2 (Nbptp2) and the transcriptional repressor for RNA polymerase II (Nbtrrp2) by Co-IP and yeast two-hybrid assays. Results from RNA interference further confirmed that the transcriptional level of and was regulated by . These results suggest that Nbssn6 impacts the infection and proliferation of via interacting with the polar tube protein and transcriptional repressor for RNA polymerase II.