NFkappaBs are a family of transcription factors best known for regulating immune responses. They have been researched extensively in vertebrates and in the last 20 years, homologs have been identified and studied. The NFkappaB family comprises two main classes, and in vertebrates class I comprises p100 and p105, and class II comprises Rel A and B and c-rel. Two NFkappaBs have been identified in B. glabrata, Bgp105 and Bgp65, from classes I and II respectively.
We initially focused on Bgp65 and hypothesized that it would play a role in the immune system, similar to what is known in vertebrates. NFkappaBs bind to specific DNA sequences (kappa-binding sites) to regulate expression of genes in the vicinity of the binding site. Many vertebrate kappa-binding sites have been identified and characterized but few have in invertebrates; at the time of performing the following study, no kappa-binding sites had been identified in the phylum Mollusca to our knowledge. We identified potential kappa-binding sites in B. glabrata and tested the ability of the Bgp65 protein to recognize these sites and bind with specificity. The sites tested were close to genes associated with immune responses, suggesting that Bgp65 may regulate immunity in this species (Humphries and Harter, 2015). Following, we used the same methods to investigate whether Bgp65 might regulate expression of components of the Toll-like receptor (TLR) pathway. The TLR pathway functions in immune responses in vertebrates and invertebrates and can activate NFkappaBs. The results of the second study suggest that Bgp65 may regulate expression of several members of the TLR pathway in B. glabrata (Humphries and Deneckere, 2018).
