Abstract
Rasgrf1 is imprinted and expressed preferentially from the paternal allele in neonatal mouse brain. At weaning, expression becomes biallelic. Using a mouse model, we assayed the effects of perturbing imprinted Rasgrf1 expression in mice with the following imprinted expression patterns: monoallelic paternal (wild type), monoallelic maternal (maternal only), biallelic (both alleles transcribed), and null (neither allele transcribed). All genotypes exhibit biallelic expression around weaning. Consequences of this transient imprinting perturbation are manifested as overall size differences that correspond to the amount of neonatal Rasgrf1 expressed and are persistent, extending into adulthood. Biallelic mice are the largest and overexpress Rasgrf1 relative to wild-type mice, null mice are the smallest and underexpress Rasgrf1 as neonates, and the two monoallelically expressing genotypes are intermediate and indistinguishable from one another, in both size and Rasgrf1 expression level. Importantly, these data support one of the key underlying assumptions of the “conflict hypothesis” that describes the evolution of genomic imprinting in mammals and supposes that equivalent amounts of imprinted gene expression produce equivalent phenotypes, regardless of which parental allele is transcribed. Concordant with the difference in overall body size, we identify differences in IGF-1 levels, both in serum protein and as liver transcript, and identify additional differential expression of components upstream of IGF-1 release in the GH/IGF-1 axis. These data suggest that imprinted Rasgrf1 expression affects GH/IGF-1 axis function, and that the consequences of Rasgrf1 inputs to this axis persist beyond the time period when expression is restricted via epigenetic mechanisms, suggesting that proper neonatal Rasgrf1 expression levels are critical for development.
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References
Alba M, Salvatori R (2004) A mouse with target ablation of the growth hormone-releasing hormone gene: a new model of isolated growth hormone deficiency. Endocrinology 145:4134–4143
Baldassa S, Gnesutta N, Fascio U, Sturani E, Zippel R (2007) SCLIP, a microtubule-destabilizing factor, interacts with RasGRF1 and inhibits its ability to promote Rac activation and neurite outgrowth. J Biol Chem 282:2333–2345
Brambilla R, Gnesutta N, Minichiello L, White G, Roylance AJ et al (1997) A role for the Ras signaling pathway in synaptic transmission and long-term memory. Nature 390:281–286
Clapcott SJ, Peters J, Orban PC, Brambilla R, Graham CF (2003) Two ENU-induced mutations in Rasgrf1 and early mouse growth retardation. Mamm Genome 14:495–505
Edwards CA, Rens W, Clarke O, Mungall AJ, Hore T et al (2007) The evolution of imprinting: chromosomal mapping of orthologues of mammalian imprinted domains in monotreme and marsupial mammals. BMC Evol Biol 7:157
Ezzat S, Yu S, Asa SL (2005) The zinc finger Ikaros transcription factor regulates pituitary growth hormone and prolactin gene expression through distinct effects on chromatin accessibility. Mol Endocrinol 19:1004–1011
Ezzat S, Mader R, Fischer S, Yu S, Ackerley C et al (2006) An essential role for the hematopoietic transcription factor Ikaros in hypothalamic-pituitary-mediated somatic growth. Proc Natl Acad Sci USA 103:2214–2219
Farnsworth CL, Freshney NW, Rosen LB, Ghosh A, Greenberg ME et al (1995) Calcium activiation of Ras mediated by neuronal exchange factor Ras-GRF. Nature 376:524–527
Ferrari C, Zippel R, Martegani E, Gnesutta N, Carrera V et al (1994) Expression of two different products of CDC25Mm, a mammalian Ras activator, during development of mouse brain. Exp Cell Res 210:353–357
Filson AJ, Louvi A, Efstratiadis A, Robertson EJ (1993) Rescue of the T-associated maternal effect in mice carrying null mutations in Igf-2 and Igf2r, two reciprocally imprinted genes. Development 118:731–736
Font De Mora J, Estaban LM, Burks DJ, Nunez A, Garces C et al (2003) Ras-GRF1 signaling is required for normal B-cell development and glucose homeostasis. EMBO J 22:3039–3049
Giese KP, Friedman E, Telliez J, Fedorov NB, Wines M et al (2001) Hippocampus-dependent learning and memory is impaired in mice lacking the Ras-guanine-nucleotide releasing factor 1 (Ras-Grf1). Neuropharmacology 41:791–800
Hegedus B, Yeh TH, Lee da Y, Emnett RJ, Li J et al (2008) Neurofibromin regulates somatic growth through the hypothalamic-pituitary axis. Hum Mol Genet 17:2956–2966
Hosui A, Hennighausen L (2008) Genomic dissection of the cytokine-controlled Stat5 signaling network in liver. Physiol Genomics 34:135–143
Innocenti M, Zippel R, Brambilla R, Sturani E (1999) CDC25Mm/Ras-GRF1 regulates both Ras and Rac signaling pathways. FEBS Lett 460:357–362
Itier J-M, Tremp GL, Leonard J-F, Multon M-C, Ret G et al (1998) Imprinted gene in postnatal growth role. Nature 393:125–126
Krapivinsky G, Krapivinsky L, Manasian Y, Ivanov A, Tyzio R et al (2003) The NMDA receptor is coupled to the ERK pathway by a direct interaction with NR2B and RasGRF1. Neuron 40:775–784
Liu JP, Baker J, Perkins AS, Robertson EJ, Efstratiadis A (1993) Mice carrying null mutations of the genes encoding insulin-like growth factor 1 (Igf-1) and type 1 IGF receptor (Igf1r). Cell 75:59–72
Liu JL, Grinberg A, Westphal H, Sauer B, Accili D et al (1998) Insulin-like growth factor-1 affects perinatal lethality and postnatal development in a gene dosage-dependent manner: manipulation using the Cre/loxP system in transgenic mice. Mol Endocrinol 12:1452–1462
Lupu F, Terwilliger JD, Lee K, Segre GV, Efstratiadis A (2001) Roles of growth hormone and insulin-like growth factor 1 in mouse postnatal growth. Dev Biol 229:141–162
Meyer CWE, Korthaus D, Jagla W, Cornali E, Grosse J et al (2004) A novel missense mutation in the mouse growth hormone gene causes semidominant dwarfism, hyperghrelinemia, and obesity. Endocrinology 145:2531–2541
Molnar A, Georgopoulos K (1994) The Ikaros gene encodes a family of functionally diverse zinc finger DNA-binding proteins. Mol Cell Biol 14:8292–8303
Molnar A, Wu P, Largespada DA, Vortkamp A, Scherer S et al (1996) The Ikaros gene encodes a family of lymphocyte-restricted zinc finger DNA binding proteins, highly conserved in human and mouse. J Immunol 156:585–592
Montminy M, Brindle P, Arias J, Ferreri K, Armstrong R (1996) Regulation of somatostatin gene transcription by cyclic adenosine monophosphate. Metabolism 45:4–7
Moore T, Haig D (1991) Genomic imprinting in mammalian development: a parental tug-of-war. Trends Genet 7:45–49
Muller EE, Locatelli V, Cocchi D (1999) Neuroendocrine control of growth hormone secretion. Physiol Rev 79:511–607
Mutsuga N, Iwasaki Y, Morishita M, Nomura A, Yamamori E et al (2001) Homeobox protein Gsh-1-dependent regulation of the rat GHRH gene promoter. Mol Endocrinol 15:2149–2156
Plass C, Shibata H, Kalcheva I, Mullins L, Kotelevtseva N et al (1996) Identification of Grf1 on mouse chromosome 9 as an imprinted gene by RLGS-M. Nat Genet 14:106–109
Pombo CA, Zalvide J, Gaylinn BD, Dieguez C (2000) Growth hormone-releasing hormone stimulates mitogen-activated kinase. Endocrinology 141:2113–2119
Scully KM, Jacobson EM, Jepsen K, Lunyak V, Viadiu H et al (2000) Allosteric effects of pit-1 DNA sites on long-term repression in cell type specification. Science 290:1127–1131
Smith FM, Garfield AS, Ward A (2006) Regulation of growth and metabolism by imprinted genes. Cytogenet Genome Res 113:279–291
Suzuki S, Renfree MB, Pask AJ, Shaw G, Kobayashi S et al (2005) Genomic imprinting of IGF2, p57(KIP2) and PEG1/MEST in a marsupial, the tammar wallaby. Mech Dev 122:213–222
Tian X, Feig LA (2006) Age-dependent participation of Ras-GRF proteins in coupling calcium-permeable AMPA-type glutamate receptors to Ras/Erk signaling in cortical neurons. J Biol Chem 281:7578–7582
Tian X, Gotoh T, Tsuji K, Lo EH, Huang S et al (2004) Developmentally regulated role for Ras-GRFs in coupling NMDA receptors to Ras, Erk, and CREB. EMBO J 23:1567–1575
Ubeda F, Wilkins JF (2008) Imprinted genes and human disease: an evolutionary perspective. Adv Exp Med Biol 626:101–115
Weidman JR, Murphy SK, Nolan CM, Dietrich FS, Jirtle RL (2004) Phylogenetic footprint analysis of IGF2 in extant mammals. Genome Res 14:1726–1732
Wilkins JF, Haig D (2003) What good is genomic imprinting: the function of parent-specific gene expression. Nat Rev Genet 4:359–368
Yang H, Mattingly RR (2006) The Ras-GRF1 exchange factor coordinates activation of H-Ras and Rac1 to control neuronal morphology. Mol Biol Cell 17:2177–2189
Yoon BJ, Herman H, Sikora A, Smith LT, Plass C et al (2002) Regulation of DNA methylation of Rasgrf1. Nat Genet 30:92–96
Yoon B, Herman H, Hu B, Park YJ, Lindroth A et al (2005) Rasgrf1 imprinting is regulated by a CTCF-dependent methylation-sensitive enhancer blocker. Mol Cell Biol 25:11184–11190
Zhou Y, Xu BC, Maheshwari HG, He L, Reed M et al (1997) A mammalian model for Laron syndrome produced by targeted disruption of the mouse growth hormone receptor/binding protein gene (the Laron mouse). Proc Natl Acad Sci USA 94:13215–13220
Acknowledgments
We thank Loren DeVito for her initial observations; Dr. Yves Boisclair and Ruqian Zhao for helpful discussions and input; and the Mouse Metabolic Phenotyping Centers at the University of Cincinnati and Vanderbilt University. Funding was from Cornell University Presidential Genomics Fellowship, NIH Training Grant T32DK007158 to Cornell University, Division of Nutritional Sciences, and R01CA098597 to PDS.
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Drake, N.M., Park, Y.J., Shirali, A.S. et al. Imprint switch mutations at Rasgrf1 support conflict hypothesis of imprinting and define a growth control mechanism upstream of IGF1. Mamm Genome 20, 654–663 (2009). https://doi.org/10.1007/s00335-009-9192-7
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DOI: https://doi.org/10.1007/s00335-009-9192-7