Gene expression analysis of wild-type and Tafazzin-deficient granulocyte-monocyte progenitor (GMP) clones (ER-HOXB8 conditionally immortalized)

Evaluate changes in gene expression resulting from the loss of the gene TAZ (protein tafazzin). Tafazzin is an enzyme involved in cardiolipin maturation and cardiolipin is a phospholipid found only in the inner mitochondrial membrane. Gene expression profiling was performed in a murine granulocyte-monocyte progenitor in vitro cell system. We identified a limited number of changes in gene expression, which was not surprising given that the tafazzin protein is localized in the mitochondria and has a very specific enzymatic activity. Genes involved in cholesterol and fatty acid metabolism (Acss1, Acat2, Ldlr), apoptosis (Bcl2, Casp3, Casp6, Cycs), and ER-stress induced apoptosis (Ddit3, Atf4) were differentially expressed (with a fold change = 1.2 and p value < 0.05). Overall design: Using a technique of retroviral ER-Hoxb8 expression (Wang et al. Nature Methods 2006), we established conditionally immortalized granulocyte-monocyte progenitors (GMPs) from TAZ-deficient and wild-type murine fetal liver hematopoietic progenitors. These GMP lines are stem cell factor (SCF) dependent and grow indefinitely in the presence of active ER-Hoxb8 (which requires the addition of beta-estradiol). Single-cell cloning was used to generate individual clones and we performed RNA-sequencing across 6 wild-type and 6 knockout clones.