title: Gene expression and IG-DMR hypomethylation of maternally expressed gene 3 in developing corticospinal neurons.
abstract: The mammalian cerebral cortex plays a central role in higher cognitive functions and in the complex task of motor control. Maternally expressed gene 3 (Meg3) appears to play a role in cortical development and neurodegeneration, but the expression and regulation of Meg3 in the cortex is not clear. In this study, we examined the expression of transcript variants of Meg3 in the developing mouse cerebral cortex. By in situ hybridization, we found that a novel transcript variant of Meg3 with 8 small exons was expressed in the developing cortex, whereas the long isoforms of Meg3 (~11 kb) were enriched in corticospinal neurons (CSNs) in layer V of the cortex. No transcript variants of Meg3 were found in the neural progenitors at E12.5, when the intergenic differential methylation region (IG-DMR) near Meg3 was highly methylated. IG-DMR became demethylated at E15.5 and remained hypomethylated in early CSNs isolated from Fezf2-EGFP transgenic mice. The expression of Meg3 transcript variant 1 was inversely correlated with the IG-DMR methylation level during development. Moreover, expression of paternally expressed gene Peg11 was limited to the upper layers, consistent with the idea that the maternally expressed gene may be preferentially transcribed in the lower layers of the cortex. The spatiotemporal expression pattern of Meg3 suggests that it may participate in the early development of CSNs and contribute to cortical malfunctions related to aberrant imprinting in Meg3.
authors.affiliation: Key Laboratory of Visual Science, National Ministry of Health, School of Optometry and Ophthalmology, Wenzhou Medical College, Wenzhou 325027, China.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Qu
authors.forename: Tian
authors.initials: T
authors.lastname: Jiang
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.forename: Xiongwei
authors.initials: X
authors.lastname: Wang
authors.forename: Huateng
authors.initials: H
authors.lastname: Cao
authors.forename: Hongping
authors.initials: H
authors.lastname: Xu
authors.forename: Jia
authors.initials: J
authors.lastname: Qu
authors.forename: Jie-Guang
authors.initials: JG
authors.lastname: Chen
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D019175:DNA Methylation; D021901:DNA, Intergenic / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018392:Genomic Imprinting; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D011712:Pyramidal Tracts / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D062085:RNA, Long Noncoding / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D021901:DNA, Intergenic; C422882:MEG3 non-coding RNA, mouse; D062085:RNA, Long Noncoding