Bebbere, Daniela Bauersachs, Stefan W. Fürst, Rainer Reichenbach, Horst-Dieter Reichenbach, Myriam Medugorac, Ivica E. Ulbrich, Susanne Wolf, Eckhard Ledda, Sergio Hiendleder, Stefan Tissue-Specific and Minor Inter-Individual Variation in Imprinting of <i>IGF2R</i> Is a Common Feature of <i>Bos taurus</i> Concepti and Not Correlated with Fetal Weight <div><p>The insulin-like growth factor 2 receptor (IGF2R) is essential for prenatal growth regulation and shows gene dosage effects on fetal weight that can be affected by <i>in-vitro</i> embryo culture. Imprinted maternal expression of murine <i>Igf2r</i> is well documented for all fetal tissues excluding brain, but polymorphic imprinting and biallelic expression were reported for <i>IGF2R</i> in human. These differences have been attributed to evolutionary changes correlated with specific reproductive strategies. However, data from species suitable for testing this hypothesis are lacking. The domestic cow (<i>Bos taurus)</i> carries a single conceptus with a similar gestation length as human. We identified 12 heterozygous concepti informative for imprinting studies among 68 <i>Bos taurus</i> fetuses at Day 80 of gestation (28% term) and found predominantly maternal <i>IGF2R</i> expression in all fetal tissues but brain, which escapes imprinting. Inter-individual variation in allelic expression bias, i.e. expression of the repressed paternal allele relative to the maternal allele, ranged from 4.6−8.9% in heart, 4.3−10.2% in kidney, 6.1−11.2% in liver, 4.6−15.8% in lung and 3.2−12.2% in skeletal muscle. Allelic bias for mesodermal tissues (heart, skeletal muscle) differed significantly (<i>P</i><0.05) from endodermal tissues (liver, lung). The placenta showed partial imprinting with allelic bias of 22.9−34.7% and differed significantly (<i>P</i><0.001) from all other tissues. Four informative fetuses were generated by <i>in-vitro</i> fertilization (IVF) with embryo culture and two individuals displayed fetal overgrowth. However, there was no evidence for changes in imprinting or DNA methylation after IVF, or correlations between allelic bias and fetal weight. In conclusion, imprinting of <i>Bos taurus IGF2R</i> is similar to mouse except in placenta, which could indicate an effect of reproductive strategy. Common minor inter-individual variation in allelic bias and absence of imprinting abnormalities in IVF fetuses suggest changes in <i>IGF2R</i> expression in overgrown fetuses could be modulated through other mechanisms than changes in imprinting.</p> </div> tissue-specific;inter-individual;imprinting;concepti;correlated;fetal 2013-04-08
    https://plos.figshare.com/articles/dataset/Tissue_Specific_and_Minor_Inter_Individual_Variation_in_Imprinting_of_IGF2R_Is_a_Common_Feature_of_Bos_taurus_Concepti_and_Not_Correlated_with_Fetal_Weight/677478
10.1371/journal.pone.0059564