title: Deficiency of the placenta- and yolk sac-specific tristetraprolin family member ZFP36L3 identifies likely mRNA targets and an unexpected link to placental iron metabolism.
abstract: The ZFP36L3 protein is a rodent-specific, placenta- and yolk sac-specific member of the tristetraprolin (TTP) family of CCCH tandem zinc finger proteins. These proteins bind to AU-rich elements in target mRNAs, and promote their deadenylation and decay. We addressed the hypotheses that the absence of ZFP36L3 would result in the accumulation of target transcripts in placenta and/or yolk sac, and that some of these would be important for female reproductive physiology and overall fecundity. Mice deficient in ZFP36L3 exhibited decreased neonatal survival rates, but no apparent morphological changes in the placenta or surviving offspring. We found Zfp36l3 to be paternally imprinted, with profound parent-of-origin effects on gene expression. The protein was highly expressed in the syncytiotrophoblast cells of the labyrinth layer of the placenta, and the epithelial cells of the yolk sac. RNA-Seq of placental mRNA from Zfp36l3 knockout (KO) mice revealed many significantly upregulated transcripts, whereas there were few changes in KO yolk sacs. Many of the upregulated placental transcripts exhibited decreased decay rates in differentiated trophoblast stem cells derived from KO blastocysts. Several dozen transcripts were deemed high probability targets of ZFP36L3; these include proteins known to be involved in trophoblast and placenta physiology. Type 1 transferrin receptor mRNA was unexpectedly decreased in KO placentas, despite an increase in its stability in KO stem cells. This receptor is crucial for placental iron uptake, and its decrease was accompanied by decreased iron stores in the KO fetus, suggesting that this intrauterine deficiency might have deleterious consequences in later life.
authors.affiliation: Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Stumpo
authors.affiliation: Laboratory of Clinical Research, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
authors.forename: Carol S
authors.initials: CS
authors.lastname: Trempus
authors.affiliation: Confocal Microscopy Core, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Tucker
authors.affiliation: Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
authors.forename: Weichun
authors.initials: W
authors.lastname: Huang
authors.affiliation: Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
authors.forename: Leping
authors.initials: L
authors.lastname: Li
authors.affiliation: TransViragen, Inc., Research Triangle Park, NC 27709, USA.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Kluckman
authors.affiliation: TransViragen, Inc., Research Triangle Park, NC 27709, USA.
authors.forename: Donna M
authors.initials: DM
authors.lastname: Bortner
authors.affiliation: Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, NC 27710, USA black009@niehs.nih.gov.
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Blackshear
mesh_terms: D000818:Animals; D047108:Embryonic Development; D005260:Female; D007501:Iron / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism; D051816:Tristetraprolin / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism; D015017:Yolk Sac / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D051816:Tristetraprolin; C530103:ZFP36L3 protein, mouse; D007501:Iron
keywords: Deadenylation; Placenta; Zinc finger proteins; mRNA binding proteins; mRNA decay