NCBI Summary:
This gene product is the founding member of the evolutionarily conserved CAN (Cerberus and DAN) family of proteins, which contain a domain resembling the CTCK (C-terminal cystine knot-like) motif found in a number of signaling molecules. These proteins are secreted, and act as BMP (bone morphogenetic protein) antagonists by binding to BMPs and preventing them from interacting with their receptors. They may thus play an important role during growth and development. Alternatively spliced transcript variants have been identified for this gene. Read-through transcripts between this locus and the upstream mitochondrial inner membrane organizing system 1 gene (GeneID 440574) have been observed. [provided by RefSeq, May 2013]
General function
Ligand, Extracellular binding protein
Comment
Cellular localization
Secreted
Comment
Ovarian function
Steroid metabolism
Comment
DAN (NBL1) Specifically Antagonizes BMP2 and BMP4 and Modulates the Actions of GDF9, BMP2, and BMP4 in the Rat Ovary. Hung WT et al. Although differential screening-selected gene aberrative in neuroblastoma (DAN, official symbol NBL1) is the founding member of the DAN subfamily of bone morphogenetic protein (BMP) antagonists, its antagonizing targets, gene regulation and physiological functions remain unclear. Using diverse cell expression systems, we found that the generation of bioactive DAN is likely to be cell type-specific. Unlike other phylogenetically close members, which are covalently linked homodimers, DAN forms a noncovalently linked homodimer during folding. Purified recombinant DAN specifically blocked signaling of BMP2 and BMP4 but not that of other ovarian-expressed transforming growth factor-?members. Although widely distributed in many organs, DAN transcript level was periodically regulated by gonadotropins. Ovarian microdissection indicated that NBL1 (DAN) mRNA is mainly expressed in granulosa cells, where its transcript level is up-regulated by the gonadotropin-driven cAMP cascade. We further investigated the local regulation and ovarian functions of DAN. NBL1 (DAN) mRNA expression in granulosa cells was up-regulated by oocyte-derived growth differentiation factor 9 (GDF9), whereas treatment with DAN significantly reversed the inhibitory effect of BMP4 on follicle-stimulating hormone-induced progesterone production in cultured granulosa cells. Our findings suggest the DAN gradient in granulosa cells, established by oocyte-derived GDF9, may serve as an antagonist barrier that modulates the actions of theca-derived BMP4 and granulosa/theca-derived BMP2 during folliculogenesis both spatially and temporally.