Figure 4.

(a) Cross-linking of thioredoxin-tagged amCLAMP^1–172 using increasing concentrations of glutaraldehyde (GA). (b) Testing of the dimerization activity of amCLAMP^1–204 using a yeast two-hybrid assay. AD stands for GAL4 activation domain and BD stands for GAL4 DNA-binding domain. Positive interaction indicates the ability of yeast to grow on assay plates without histidine. Assay plates are shown in the Figure S2. (c) Schematic representation of rescue constructs expressing 3xHA-tagged CLAMP proteins under the control of ubiquitin-p63E promoter; SV40 poly(A)–SV40 polyadenylation signal; attB is the site for φC31-mediated recombination used for site-specific insertion of the construct; yellow represents the intronless yellow gene used as a reporter. (d) Effect of deletion of the dimerization domain in the HA-tagged CLAMP proteins on their recruitment to the chromatin shown by immunostaining of polytene chromosomes with anti-HA and anti-MSL2 antibodies in males and females. Scale bar is 20 μm.