Dynamics of reporter gene stimulation by HMG box proteins

Reporter gene stimulation by MIDA1 through its DnaJ homology region

MIDA1 was reported as a protein that can associate with Id1. Its N-terminus has homology to Z-DNA binding protein, Zuotin, that contains DnaJ motif, considered to interact with Hsp70s, and Id binding domain. In the present study, we found that MIDA1 stimulates the transcription of the co-transfected genes. This stimulation was independent of promoter specificity because it was observed in various transfected genes. MIDA1 enhanced formation of DNA-protein complexes with E-box or TATA box without its direct binding to DNA. Analysis with deletion mutants of MIDA1 showed that the short protein fragment containing DnaJ motif within Zuotin homology region is sufficient for the stimulation of transcription and we demonstrated that MIDA1 associates with Hsp70. These data suggest involvement of MIDA1 in the stimulation of transcription in concert with Hsp70/Hsc70 molecular chaperones, thus providing a link between Hsp70/Hsc70 molecular chaperones and components of the transcriptional machinery.

Transcription factor decoy (TFD) in breast cancer research and treatment

Synthetic oligonucleotides have recently been the object of many investigations aimed to develop sequence-selective compounds able to modulate, either positively or negatively, transcription of eukaryotic and viral genes. Alteration of transcription could be obtained by using synthetic oligonucleotides mimicking target sites of transcription factors (the transcription factor decoy -TFD- approach). This could lead to either inhibition or activation of gene expression, depending on the biological functions of the target transcription factors. Since several transcription factors are involved in tumor onset and progression, this issue is of great interest in order to design anti-tumor compounds. In addition to oligonucleotides, peptide nucleic acids (PNA) can be proposed for the modulation of gene expression. In this respect, double-stranded PNA-DNA chimeras have been shown to be capable to exhibit strong decoy activity. In the case of treatment of breast cancer cells, decoy oligonucleotides mimicking CRE binding sites, promoter region of estrogen receptor alpha gene, NF-kB binding sites have been used with promising results. Therefore, the transcription factor decoy approach could be object of further studies to develop protocols for the treatment of breast cancer. In the future, transcription factors regulating cell cycle, hormone-dependent differentiation, tumor invasion and metastasis are expected to be suitable targets for transcription factor decoy.