The BSD domain was first identified by a computational analysis in the BTF2-like transcription factor (Yeast), synapse-associated (Drosophila) and DOS2-like (Yeast) proteins.  The BSD domain is an average of 60 amino acids, characterized by three predicted alpha helices, which probably form a three-helical bundle, as well as by conserved tryptophan and phenylalanine residues, located at the C terminus of the domain (Interpro domain IPR005607). It is found preceding BTB domains, a protein protein interaction domain often found in transcription factors, suggesting a possible DNA binding role (Doerks et al., 2002, PMID: 11943536) as well as U-box domains (PMID:15772280). The Syap1 gene in mouse is a well studied BSD transcription factor (Schmitt et al., 2016, PMID: 27344443) The third predicted helix contains neighboring phenylalanine and tryptophan residues - less common amino acids that are invariant in all the BSD domains identified and that are the most striking sequence features of the domain

In  Arabidopsis, the N-terminus region of the AtBSD1 protein has been proposed as a transcriptional activator as indicated by a yeast transcriptional activity assay (Park, J et al., 2009).  Similarly the SlBSD1 protein from tomato was found to be targeted to the nucleus in plant cells and acted as a transcriptional activator in a yeast transcriptional activity assay (Fan et al., 2020, PMID: 32845982). Neither of these have been shown to bind DNA directly, however, the MaBSD1 protein from banana  was shown to activate the expression of two cell wall modification-related genes, MaEXP1/2, via directly interacting with their promoters in a transient protoplast assay (Ba et al., 2014, PMID: 25097074).

Last updated June 2023 by John Gray

References:

Doerks T, Huber S, Buchner E, Bork P. BSD: a novel domain in transcription factors and synapse-associated proteins. Trends Biochem Sci. 2002 Apr;27(4):168-70. doi: 10.1016/s0968-0004(01)02042-4. PMID: 11943536.

Schmitt D, Funk N, Blum R, Asan E, Andersen L, Rülicke T, Sendtner M, Buchner E. Initial characterization of a Syap1 knock-out mouse and distribution of Syap1 in mouse brain and cultured motoneurons. Histochem Cell Biol. 2016 Oct;146(4):489-512. doi: 10.1007/s00418-016-1457-0. Epub 2016 Jun 25. PMID: 27344443; PMCID: PMC5037158.

Park J, Kim MJ, Jung SJ, Suh MC. 2009. Identification of a novel transcription factor, AtBSD1, containing a BSD domain in Arabidopsis thaliana. Journal of Plant Biology 52, 141–146.

Fan Y, Niu X, Huang L, Gross R, Lu H, Hawkins M, Yuan Y, Miao M, Liu Y, Xiao F. A novel BSD domain-containing transcription factor controls vegetative growth, leaf senescence, and fruit quality in tomato. J Exp Bot. 2020 Dec 31;71(22):6945-6957. doi: 10.1093/jxb/eraa393. PMID: 32845982.

Ba LJ, Shan W, Xiao YY, Chen JY, Lu WJ, Kuang JF. A ripening-induced transcription factor MaBSD1 interacts with promoters of MaEXP1/2 from banana fruit. Plant Cell Reports, [s. l.], v. 33, n. 11, p. 1913–1920, 2014. DOI 10.1007/s00299-014-1668-6. Epub 2014 Aug 6. PMID: 25097074.