Taxonomic distribution of proteins containing BTD domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing BTD domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Fungal CSL transcription factors.

Prevorovsky M, Puta F, Folk P
BMC Genomics. 2007; 8: 233-233

BACKGROUND: The CSL (CBF1/RBP-Jkappa/Suppressor of Hairless/LAG-1) transcription factor family members are well-known components of the transmembrane receptorNotch signaling pathway, which plays a critical role in metazoan development.They function as context-dependent activators or repressors of transcription oftheir responsive genes, the promoters of which harbor the GTG(G/A)GAA consensuselements. Recently, several studies described Notch-independent activities of theCSL proteins. RESULTS: We have identified putative CSL genes in several fungalspecies, showing that this family is not confined to metazoans. We have analyzed their sequence conservation and identified the presence of well-defined domainstypical of genuine CSL proteins. Furthermore, we have shown that the candidatefungal protein sequences contain highly conserved regions known to be requiredfor sequence-specific DNA binding in their metazoan counterparts. Thephylogenetic analysis of the newly identified fungal CSL proteins revealed theexistence of two distinct classes, both of which are present in all the speciesstudied. CONCLUSION: Our findings support the evolutionary origin of the CSLtranscription factor family in the last common ancestor of fungi and metazoans.We hypothesize that the ancestral CSL function involved DNA binding andNotch-independent regulation of transcription and that this function may still beshared, to a certain degree, by the present CSL family members from both fungiand metazoans.

Crystal structure of the nuclear effector of Notch signaling, CSL, bound to DNA.

Kovall RA, Hendrickson WA
EMBO J. 2004; 23: 3441-51

Notch signaling is a conserved pathway of communication between neighboring cellsthat results in cell fate specification, and CSL is the universal transcriptionaleffector of Notch signaling. The Notch intracellular domain translocates to thenucleus after proteolytic release upon Notch extracellular engagement, and there it displaces corepressors from DNA-bound CSL and recruits activators of Notchtarget genes. Here we report the 2.85 A crystal structure of CSL with a targetDNA. CSL comprises three structurally integrated domains: its amino (NTD)- andcarboxy (CTD)-terminal domains are strikingly similar to those of Reltranscription factors, but a surprising beta-trefoil domain (BTD) is insertedbetween them. CSL-bound DNA is recognized specifically by conserved residues fromNTD and BTD. A hydrophobic pocket on BTD is identified as the likely site ofNotch interaction with CSL, which has functional implications for the mechanismof Notch signaling.