JBP2 subfamily

The JBP2 subfamily takes its name from the Trypanosoma brucei J Binding Protein 2 which regulates insertion of an unusual glycosylated thymine-derived base, J, which marks silenced telomeric DNA 1.

Interestingly, both DRD1 and JBP2 are involved in processes which target modifications at the C5 position of the pyrimidine ring which will be exposed in the major groove. JBP2 and DRD1 members show sequence similarity, but have been conservatively assigned to separate subfamilies due to their distinct evolutionary ranges and the limited numbers of members available. The identification of a DRD1 subfamily member in Dictyostelium discoideum suggests that the subfamilies may be more widespread than indicated by the current small sample set.

The L. major, T. brucei and T. cruzi genomes with JBP2 subfamily members also contain proteins which are assigned by the HMM profiles to the Arip4 subfamily. The function of Arip4 is unknown but members are otherwise found in higher fungi and animals, but not in DRD1-containing plants. It is therefore possible that a relationship encompasses not only DRD1 and JBP2, but also Arip4.

names associated with subfamily members
1: DiPaolo, C., R. Kieft, et al. (2005). Regulation of trypanosome DNA glycosylation by a SWI2/SNF2-like protein. Mol Cell 17(3): 441-51. PubMed