(25). Among the subfamilies now designated as AT-specific, only DRIL2 (ARID3B) and ARID3C have not been tested empirically, but again, there is at least 75% identity and more than 90% similarity between these ARID sequences and the AT-specific prototypes Bright and Dri. There is a potential conflict between our conclusions and a report suggesting that an ARID-containing fusion peptide of jumonji (JARID2) may have general selectivity for AT-rich sequences, since a majority of sequences selected by jumonji from a pool of random oligonucleotides were AT rich (34). However, several sequences that jumonji bound with equally high affinity in that study were not AT rich, and a precise consensus site could not be identified. The present survey is concerned with the properties inherent in the ARID sequence from each subfamily. As such, it was conducted with fusion proteins expressing the respective ARID sequences separate from the context of the native proteins. It remains possible that the endogenous proteins acquire a degree of sequence-specific binding behavior in physiological conditions.
