Perinatal methylmercury exposure perturbs the expression of Plp1 and Cnp splice variants in cerebellum of rat pups.
Early life exposure to environmental chemicals can interfere with myelin formation in the developing brain, leading to neurological disorders. The Proteolipid Protein 1 (Plp1), Myelin Basic Protein (Mbp) and 2',3'-Cyclic Nucleotide 3'Phosphodiesterase (Cnp) genes expressed in oligodendrocytes and involved in myelination processes can be useful biomarkers of potential developmental neurotoxicity. In an earlier study, we concluded that the reduction in the expression levels of Mbp splice variants in juvenile rat cerebellum following perinatal methylmercury (MeHg) exposure were compatible with an overall reduction of mature oligodendrocytes population. This observation prompted us to analyze the expression of Plp1 and Cnp in developing rat cerebellum to further confirm and investigate the toxic effects of MeHg on vulnerable oligodendrocytes. Splice variants of Plp1 in human and of Cnp in mouse are curated in NCBI RefSeq database, but not for rat. Lack of annotation of splice variants can pose significant challenge for the reliable quantification of gene expression levels in toxicological studies. Therefore, we applied a "comparative sequence analysis" approach, relying on annotated splice variants in human/mouse and on evolutionary conservation of intron-exon structures, to identify additional splice variants of Plp1 and Cnp in rat. Then, we confirmed their identity by nucleotide sequencing and characterized their temporal expression patterns during brain development by RT-PCR. The measurement of total transcripts and individual splice variants of Plp1 and Cnp in the cerebellum of MeHg-exposed rat pups revealed a relatively similar level of reduction in their expression levels. This study further confirms that perinatal exposure to MeHg can impact oligodendrocytes in pups. Based on these observations, we conclude that monitoring the expression of these oligodendrocyte-enriched genes can be useful to identify toxic chemicals affecting myelination.
Hazard Identification Division, HECSB, Health Canada, Tunney's Pasture, Ottawa, Ontario K1A 0L2, Canada. Electronic address: bhaja.krushna.padhi@hc-gc.gc.ca.
Bhaja K
BK
Padhi
Hazard Identification Division, HECSB, Health Canada, Tunney's Pasture, Ottawa, Ontario K1A 0L2, Canada.
Marianela
M
Rosales
Hazard Identification Division, HECSB, Health Canada, Tunney's Pasture, Ottawa, Ontario K1A 0L2, Canada.
Guillaume
G
Pelletier
D063309:2',3'-Cyclic Nucleotide 3'-Phosphodiesterase / Q000235:genetics / Q000378:metabolism*; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D002531:Cerebellum / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D019295:Computational Biology; D017124:Conserved Sequence; D030541:Databases, Genetic; D015536:Down-Regulation; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005819:Genetic Markers; D005865:Gestational Age; D006801:Humans; D008767:Methylmercury Compounds / Q000633:toxicity*; D051379:Mice; D018991:Myelin Proteolipid Protein / Q000235:genetics / Q000378:metabolism*; D009836:Oligodendroglia / Q000187:drug effects* / Q000378:metabolism; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
D005819:Genetic Markers; D008767:Methylmercury Compounds; D018991:Myelin Proteolipid Protein; C489071:Plp1 protein, rat; D020033:Protein Isoforms; D012333:RNA, Messenger; D063309:2',3'-Cyclic Nucleotide 3'-Phosphodiesterase; C571339:Cnp protein, rat
Cyclic Nucleotide 3′Phosphodiesterase; Methylmercury; Proteolipid Protein 1; Rat; Splice variants