The GAGA transcription factor binds to the promoter region of the Heat Shock Protein 70 (see Fig. 1) and participate in chromatin re-arrangements linked with transcription activation. GAGA factor can multimerize and preliminary results suggest specific conformational changes associated with its self-association. We have started investigating the structure of DNA-GAGA complexes in the context of chromatin folding. Early results strongly suggest that the GAGA multimer forms a complex of size close to that of an individual nucleosome. We are now investigating the contribution of such a complex to chromatin higher-order structure (see Fig. 2).