Expression of Gal4-VP16 and Gal4-DNA binding domain under the control of the T lymphocyte-specific lck proximal promoter in transgenic mice

Thymocyte-specific transcriptional regulatory systems can be used to better understand the relationship between transcription and V(D)j recombination during early T cell development. In this study, we generated transgenic mice expressing the transactivator Gal4-VP16 or the Gal4 DNA binding domain (Gal4-DBD) under the control of the lck proximal promoter, which is only active in immature thymocytes. From these studies Gal4-VP16 and Gal4-DBD expression was shown to significantly alter thymic cellularity and differentiation without significantly changing the CD3(+) thymocyte distribution. Furthermore, the presence of Gal4-VP16 or Gal4-DBD in the transgenic thymocytes retarded the mobility of the Gal4 DNA binding motif as determined by a gel mobility shift assay, suggesting that the developmental alteration did not affect the functional property of the transgenic proteins. These results indicated that lck promoter-driven Gal4-VP16 or Gal4-DBD expression did not affect CD3(+) mature thymocytes, thus this system can be applied to study transcriptional regulation of trans-responder genes in bigenic mouse model thymocytes.