title: Effects of Combined Tristetraprolin/Tumor Necrosis Factor Receptor Deficiency on the Splenic Transcriptome.
abstract: Tristetraprolin (TTP) acts by binding to AU-rich elements in certain mRNAs, such as tumor necrosis factor (TNF) mRNA, and increasing their decay rates. TTP knockout mice exhibit a profound inflammatory syndrome that is largely due to increased TNF levels. Although TTP's effects on gene expression have been well studied in cultured cells, little is known about its functions in intact tissues. We performed deep RNA sequencing on spleens from TTP knockout mice that were also deficient in both TNF receptors ("triple knockout" mice) to remove the secondary effects of excess TNF activity. To help identify posttranscriptionally regulated transcripts, we also compared changes in mature mRNA levels to levels of transiently expressed pre-mRNA. In the triple knockout spleens, levels of 3,014 transcripts were significantly affected by 1.5-fold or more, but only a small fraction exhibited differential mRNA/pre-mRNA changes suggestive of increased mRNA stability. Transferrin receptor mRNA, which contains two highly conserved potential TTP binding sites, was significantly upregulated relative to its pre-mRNA. This was reflected in increased transferrin receptor expression and increased splenic iron/hemosiderin deposition. Our results suggest that TTP deficiency has profound effects on the splenic transcriptome, even in the absence of secondary increases in TNF activity.
authors.affiliation: Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
authors.forename: Sonika
authors.initials: S
authors.lastname: Patial
authors.affiliation: Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Stumpo
authors.affiliation: Section on Neural Gene Expression, National Institute of Mental Health, Bethesda, Maryland, USA.
authors.forename: W Scott
authors.initials: WS
authors.lastname: Young
authors.affiliation: Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Ward
authors.affiliation: Laboratory of Experimental Pathology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
authors.forename: Gordon P
authors.initials: GP
authors.lastname: Flake
authors.affiliation: Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina, USA black009@niehs.nih.gov.
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Blackshear
mesh_terms: D000818:Animals; D001665:Binding Sites; D005091:Exons; D005786:Gene Expression Regulation; D007438:Introns; D008297:Male; D018345:Mice, Knockout; D012333:RNA, Messenger; D011990:Receptors, Transferrin / Q000235:genetics; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000235:genetics* / Q000378:metabolism; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000235:genetics* / Q000378:metabolism; D017423:Sequence Analysis, RNA; D013154:Spleen / Q000276:immunology / Q000502:physiology*; D059467:Transcriptome; D051816:Tristetraprolin / Q000235:genetics* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D011990:Receptors, Transferrin; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; C480029:Tfrc protein, mouse; C506236:Tnfrsf1a protein, mouse; D051816:Tristetraprolin