Loss of Srf deregulates expression of the integrin network and impairs stem cell and MPP adhesion to synthetic substrates. (A) Heat map representation of the transcripts abundance of genes associated to the integrin signaling pathway identified in Srf^{Δ/Δ;Mx1-Cre} LSKs. Black indicates high abundance and gray/white low abundance of each transcript. Gene names are indicated. Map was obtained using the Ingenuity Pathway Analysis. (B) qRT-PCR analysis of the expression levels of genes associated to the integrin signaling pathway or encoding for actomyosin cytoskeleton components, in Lineage (Lin)-negative cell populations from Srf^{Δ/Δ;Mx1-Cre} mice. Expression levels were normalized to Gapdh, and results were expressed relative to gene expression levels in Srf^+/+;Mx1-Cre mice (set to 1). Values shown are the mean ± SEM from 2 independent experiments. (C) Representative FACS profile of α2, α4, α5, β1, β2 integrins and CD44 expression on the surface of Srf^+/+;Mx1-Cre and Srf^{Δ/Δ;Mx1-Cre} LSK (n = 4 per genotype; 5 weeks after pIpC treatment). The mean fluorescence intensity (MFI) ± standard deviation is indicated. (D) Ex vivo adhesion properties of Srf^+/+;Mx1-Cre and Srf^{Δ/Δ;Mx1-Cre} LSKs. Cells were counted 2 hours after plating onto synthetic matrix-coated wells. Background adhesion of LSKs on uncoated slides was subtracted from each value. Two independent experiments were performed, and each condition was analyzed in triplicate or more; data represent means ± SEM (n = 4 for each genotype, *P < .05 by Mann- Whitney test).