Wild-type and tafazzin-deficient clones of granulocyte-monocyte progenitors (GMP), ER-HOXB8 conditionally immortalized, immature, in estrogen.
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. 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 5 knockout clones.