WSTF (Williams Syndrome Transcription Factor) is an extremely versatile protein and is involved in several molecular events including vitamin D dependent transcription, vitamin D metabolism, DNA repair and the transcription of the RNA polymerase I and III genes. WSTF is a subunit of three ATP-dependent chromatin remodeling complexes designated WINAC, WICH and B-WICH. In this study, the effect of the bromodomain of the WSTF protein and a histidine protein tag on the interaction of WSTF with its binding partners, SNF2h and nuclear myosin 1, in the B-WICH complex has been studied. WSFT, SNF2h and nuclear myosin 1 are the three subunits of the B-WICH complex identified to be involved in the transcription of genes transcribed by the enzymes polymerase I and III. Furthermore a comparison between the histidine, V5 and HA protein tags on their expression of the WSTF protein has been carried out. The effect of the His, V5 and HA protein tags as well as the role of the bromodomain on the localization of WSTF in HeLa cells has also been investigated.