Transcription profiling of mouse fetal liver

ABSTRACT: Iron is essential for all cells but is toxic in excess, so iron absorption and distribution are tightly regulated. Serum iron is bound to transferrin and primarily enters erythroid cells via receptor-mediated endocytosis of the transferrin receptor (Tfr1). Tfr1 is essential for developing erythrocytes and reduced Tfr1 expression is associated with anemia. The transcription factors STAT5A/B are activated by many cytokines, including erythropoietin. Stat5a/b-/- mice are severely anemic and die perinatally, but no link has been made to iron homeostasis. To study the function of STAT5A/B in vivo, we deleted the floxed Stat5a/b locus in hematopoietic cells with a Tie2-Cre transgene. These mice exhibited microcytic, hypochromic anemia, as did lethally irradiated mice transplanted with Stat5a/b-/- fetal liver cells. Flow cytometry and RNA analyses of erythroid cells from mutant mice revealed a 50% reduction in Tfr1 mRNA and protein. We detected STAT5A/B binding sites in the first intron of the Tfr1 gene and found that expression of constitutively active STAT5A in an erythroid cell line increased Tfr1 levels. Chromatin immunoprecipitation experiments confirmed the binding of STAT5A/B to these sites. We conclude that STAT5A/B is an important regulator of erythroid progenitor iron uptake via its control of Tfr1 transcription. Experiment Overall Design: Isolated Ter119-positive fetal liver cells from three to five E14.5 embryos of the same genotype were combined, and total RNA was extracted using TRIzol reagent (Life Technologies) with two additional ethanol precipitations. RNA quality was verified using an Agilent Bioanalyzer (Agilent Technologies). Microarray analyses were performed using Affymetrix Mouse Genome 430 2.0 array GeneChips (Affymetrix). Up- and down-regulated genes were selected based on P values of <0.05 and fold changes of >1.5 or -1.5 as assessed by ANOVA using Partek Pro software (Partek). To determine specific pathways, gene pathway analysis was obtained using the statistically significant gene list (P<0.05) represented on the chip.

ORGANISM(S): Mus musculus

SUBMITTER: Bing Mei Zhu 

PROVIDER: E-GEOD-11777 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress