Fig. 1. Multiple trxG genes are essential for functioning of the bxd TRE/PRE maintenance element. (A) The effects of ash1²² and Asx³ on the eye color of C1 transgenic flies. (B) Map of trxG and PcG response elements in the bxd region of Ubx based on the results of the genetic white tests shown in Tables 1 and 2. Data from Table 1: genes that interact or do not interact with the bxd N constructs are shown in red and black, respectively, above the map. Data from Table 2: a scheme of the C constructs used in these experiments is shown at the bottom. The B TRE has been deleted in the constructs because of redundancy with the C TRE (Tillib et al., 1999). Mapped Trx, Asx, Ash1 and Brm response elements are in red. Previously mapped PcG response elements are in green (Tillib et al., 1999).