Auto-regulation of Slug mediates its activity during epithelial to mesenchymal transition

• Published in: Biochimica et biophysica acta Vol. 1849; no. 9; pp. 1209 - 1218
• Main Authors: Kumar, Brijesh, Uppuladinne, Mallikarjunachari V.N., Jani, Vinod, Sonavane, Uddhavesh, Joshi, Rajendra R., Bapat, Sharmila A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-09-2015
• Subjects: Autoregulation; Cell Line, Tumor; EMT; Epithelial-Mesenchymal Transition - physiology; Female; Gene Expression Regulation - genetics; Humans; Ovarian Neoplasms - genetics; Ovarian Neoplasms - pathology; Promoter Regions, Genetic; Protein Binding; Slug; Snail Family Transcription Factors; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription Factors - physiology; Transcription, Genetic - genetics; SS; Autoregulation; MMPSBA; ZF; ChIP; Slug; EMT; PDB; TF; TSS; EMSA; MD; TGF-β
• ISSN: 1874-9399; 0006-3002; 1876-4320
• DOI: 10.1016/j.bbagrm.2015.07.006

Slug, a five C2H2 zinc finger (ZF) motif transcription factor mediates cell migration in development, adult tissue repair and regeneration, as well as during tumor metastases through epithelial to mesenchymal transition. At the molecular level, this involves interactions with E-box (CACC/GGTG) consensus elements within target gene promoters to achieve transcriptional repression. However, precise elucidation of events involved in this DNA recognition and binding of specific promoters to regulate target genes have not been achieved. In the present study, we show that besides transcriptional repression, Slug can also directly activate its own expression by preferential binding to specific E-box elements in the distal binding region of its promoter. Our findings suggest that while the first ZF does not contribute to the transcription-associated functions of Slug, all the remaining four ZFs are involved in regulating the expression of target genes with ZF3 and ZF4 being more crucial than ZF2 or ZF5. We also report that recognition and binding preferences of ZFs are defined through intrinsic differences in the E-box core base pairs and/or flanking sequences, with the S2 E-box element being most critical during autoregulation. However, specific target E-box recognition and binding are also defined by the cellular context, which implies that in silico and/or biochemical DNA binding preferences may not necessarily be able to accurately predict in situ events. Our studies thus constitute a novel understanding of transcriptional regulation.
•Slug mediates autoactivation through a positive feedback loop.•S2 E-box (−1817 to −1812) in distal Slug promoter is involved in autoregulation.•Zinc fingers ZF3 and ZF4 are more crucial than ZF2 or ZF5 for autoregulation.