Histone deacetylases play an important role in modulating chromatin thereby influencing transcriptional identities of cells. HDAC7, a class II HDAC, is predominantly expressed in vertebrate cells during early development but the exact function of this protein is unknown. In preliminary studies, we discovered HDAC7 to be critical in AML cells as silencing of HDAC7 resulted in reduced viability. Our experiments have focused on determining the intracellular dynamics of HDAC7 and subsequently understanding its genomic binding profile in AML.
Methods: We used subcellular fractionation of cell lysates and performed western blots to determine the presence of HDAC7 in four different AML lines. We also utilized quantitative-PCR to determine the transcript levels in the same cell lines. Finally, ongoing work includes construction and viral transduction of GFP-tagged overexpression vectors to visualize HDAC7 localization via confocal microscopy.
Results: We discovered significant expression of HDAC7 in all AML lines (OCI-2, OCI-3, MV411 and Molm13) via qPCR. However, western blots showed HDAC7 in the cytosolic but not the nuclear fraction (insoluble chromatin bound or soluble nuclear fractions).
Discussion: The lack of HDAC7 complicates the elucidation of the genomic binding as lack of detectable protein in the nucleus adds technical challenges. We are now performing overexpression experiments in addition to blocking nuclear export of proteins via Leptomycin B to determine if HDAC7 can be captured in the nucleus. If successful we can perform ChIP-seq experiments to map the HDAC7 mediated aberrant transcriptional profile to better understand mechanisms contributing to leukemogenesis.
Recommended CitationSingh, Rajat; Romer-Seibert, Jennifer; and Meyer, Sara, "Elucidating the role of HDAC7 in Acute Myeloid Leukemia" (2020). Phase 1. Paper 15.