Abstract
Background: Thrombocytopenia 2, an autosomal dominant inherited disease characterized by moderate thrombocytopenia, predisposition to myeloid malignancies and normal platelet size and function, can be caused by 5'-untranslated region (UTR) point mutations in ankyrin repeat domain containing 26 (ANKRD26). Runt related transcription factor 1 (RUNX1) and friend leukemia integration 1 (FLI1) have been identified as negative regulators of ANKRD26. However, the positive regulators of ANKRD26 are still unknown. Aim: To prove the positive regulatory effect of GATA binding protein 2 (GATA2) on ANKRD26 transcription. Methods: Human induced pluripotent stem cells derived from bone marrow (hiPSC-BM) and urothelium (hiPSC-U) were used to examine the ANKRD26 expression pattern in the early stage of differentiation. Then, transcriptome sequencing of these iPSCs and three public transcription factor (TF) databases (Cistrome DB, animal TFDB and ENCODE) were used to identify potential TF candidates for ANKRD26. Furthermore, overexpression and dual-luciferase reporter experiments were used to verify the regulatory effect of the candidate TFs on ANKRD26. Moreover, using the GENT2 platform, we analyzed the relationship between ANKRD26 expression and overall survival in cancer patients. Results: In hiPSC-BMs and hiPSC-Us, we found that the transcription levels of ANKRD26 varied in the absence of RUNX1 and FLI1. We sequenced hiPSC-BM and hiPSC-U and identified 68 candidate TFs for ANKRD26. Together with three public TF databases, we found that GATA2 was the only candidate gene that could positively regulate ANKRD26. Using dual-luciferase reporter experiments, we showed that GATA2 directly binds to the 5'-UTR of ANKRD26 and promotes its transcription. There are two identified binding sites of GATA2 that are located 2 kb upstream of the TSS of ANKRD26. In addition, we discovered that high ANKRD26 expression is always related to a more favorable prognosis in breast and lung cancer patients. Conclusion: We first discovered that the transcription factor GATA2 plays a positive role in ANKRD26 transcription and identified its precise binding sites at the promoter region, and we revealed the importance of ANKRD26 in many tissue-derived cancers.