Bombyx mori UFBP1 regulates apoptosis and promotes BmNPV proliferation by affecting the expression of ER chaperone BIP

Ubiquitin-fold modifier 1 (UFM1) is attached to protein substrates through the sequential activity of an E1 (UBA5)-E2 (UBC1)-E3 (UBL1) cascade. UFBP1 is a conserved UFL1-interacting protein in mammals. However, there is no study on UFBP1 in silkworm yet. In this study, we identified a UFBP1 ortholog in B. mori genome. Spatio-Temporal expression profiles showed that BmUFBP1 expression was highly in midgut, fatbody, and at the moth stage. BmUFBP1 knockdown inhibited ER-stress induced ER chaperone expression and BmNPV proliferation, while BmUFBP1 overexpression increased BmNPV proliferation. Furthermore, RNA sequencing and experimental verification identified the HSP70 family member BmBIP as the BmUFBP1 downstream target in regulating BmNPV proliferation. Overall, these results suggest that BmUFBP1 facilitates BmNPV proliferation via ATF6-BIP signaling. siNC siUFBP1