ABSTRACT
Genomic imprinting is an allelic gene expression phenomenon primarily controlled by allele-specific DNA methylation at the imprinting control region (ICR), but the underlying mechanism remains largely unclear. N-α-acetyltransferase 10 protein (Naa10p) catalyzes N-α-acetylation of nascent proteins, and mutation of human Naa10p is linked to severe developmental delays. Here we report that Naa10-null mice display partial embryonic lethality, growth retardation, brain disorders, and maternal effect lethality, phenotypes commonly observed in defective genomic imprinting. Genome-wide analyses further revealed global DNA hypomethylation and enriched dysregulation of imprinted genes in Naa10p-knockout embryos and embryonic stem cells. Mechanistically, Naa10p facilitates binding of DNA methyltransferase 1 (Dnmt1) to DNA substrates, including the ICRs of the imprinted allele during S phase. Moreover, the lethal Ogden syndrome-associated mutation of human Naa10p disrupts its binding to the ICR of H19 and Dnmt1 recruitment. Our study thus links Naa10p mutation-associated Ogden syndrome to defective DNA methylation and genomic imprinting.
Subject(s)
DNA (Cytosine-5-)-Methyltransferases/genetics , Developmental Disabilities/genetics , Epigenesis, Genetic , Genomic Imprinting , N-Terminal Acetyltransferase A/genetics , N-Terminal Acetyltransferase E/genetics , RNA, Long Noncoding/genetics , Animals , DNA/genetics , DNA/metabolism , DNA (Cytosine-5-)-Methyltransferase 1 , DNA (Cytosine-5-)-Methyltransferases/metabolism , DNA Methylation , Developmental Disabilities/metabolism , Developmental Disabilities/pathology , Disease Models, Animal , Embryo, Mammalian , Female , Gene Deletion , Genes, Lethal , Genome-Wide Association Study , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mouse Embryonic Stem Cells/metabolism , Mouse Embryonic Stem Cells/pathology , N-Terminal Acetyltransferase A/deficiency , N-Terminal Acetyltransferase E/deficiency , Protein Binding , RNA, Long Noncoding/metabolism , S Phase/geneticsABSTRACT
Transcription factors play a key role in maintaining cell identity. One mechanism of such cell memory after multiple rounds of cell division cycles is through persistent mitotic chromosome binding, although how individual transcription factors achieve mitotic chromosome retention is not completely understood. Here we show that PAX6, a lineage-determining transcription factor, coats mitotic chromosomes. Using deletion and point mutants associated with human ocular diseases in live-cell imaging analysis, we identified two regions, MCR-D1 and MCR-D2, that were responsible for mitotic chromosome retention of PAX6. We also identified three nuclear localization signals (NLSs) that contributed to mitotic chromosome retention independent of their nuclear import functions. Full mitotic chromosome retention required the presence of DNA-binding domains as well as NLSs within MCR-Ds. Furthermore, disease-associated mutations and NLS mutations changed the distribution of intrinsically disordered regions (IDRs) in PAX6. Our findings not only identify PAX6 as a novel mitotic chromosome retention factor but also demonstrate that the mechanism of mitotic chromosome retention involves sequence-specific DNA binding, NLSs, and molecular conformation determined by IDRs. These findings link mitotic chromosome retention with PAX6-related pathogenesis and imply similar mechanisms for other lineage-determining factors in the PAX family.