Microarray analysis of Sclfl/fl fetal liver progenitor cell lines identifies candidate target genes for Scl/Tal1. (A) Hematopoietic progenitor cell lines were generated from fetal livers of E12.5 Sclfl/fl embryos by immortalization with Hox11 retrovirus (Sclfl/fl parental cell line). Deletion of Scl gene was achieved by transduction with a Cre-GFP retroviral vector (SclΔ/Δ). Scl-deficienT cells exhibited impaired megakaryocytic maturation demonstrated by the loss of AchE activity. Reintroduction of Scl expression with an Scl retroviral vector rescued the megakaryocytic maturation defect (SclΔ/Δ+Scl). After 5 days of culture with TPO and IL-3, the cell lines were harvested and subjected to Affymetrix gene expression analysis to identify Scl-dependent genes. (Sections were analyzed on a Zeiss Axiovert 40 CFL microscope. Images were captured using a Canon PC1089. Magnification, ×40.) (B) Analysis of the top 50 genes that were down-regulated on loss of Scl reveals genes known to be involved in hematopoiesis and vasculogenesis, as well as unknown ESTs and cDNAs (i). Myocyte enhancer factor 2C (Mef2C) was one of the genes whose expression was down-regulated in the absence of Scl, and rescued on reintroduction of Scl. (ii) The bar graph depicts the average expression of Mef2C across 3 different probes in one experiment.
