Linking Chromosomal Silencing With Expression From Autosomal Integrated Transgenes.

is the master regulator of X-Chromosome Inactivation (XCI), the mammalian dosage compensation mechanism that silences one of the two X chromosomes in a female cell. XCI is established during early embryonic development. transgene (Tg) integrated into an autosome can induce transcriptional silencing of flanking genes; however, the effect and mechanism of RNA on autosomal sequence silencing remain elusive.

Exportins can inhibit major mitotic assembly events : membrane fusion, nuclear pore formation, and spindle assembly.

egg extracts are a powerful tool for studying complex biological processes, including nuclear reconstitution, nuclear membrane and pore assembly, and spindle assembly. Extracts have been further used to demonstrate a moonlighting regulatory role for nuclear import receptors or on these cell cycle assembly events. Here we show that can also play a role in these events.

Functional Conservation of LncRNA JPX Despite Sequence and Structural Divergence.

Long noncoding RNAs (lncRNAs) have been identified in all eukaryotes and are most abundant in the human genome. However, the functional importance and mechanisms of action for human lncRNAs are largely unknown. Using comparative sequence, structural, and functional analyses, we characterize the evolution and molecular function of human lncRNA JPX.

LncRNA Jpx induces Xist expression in mice using both trans and cis mechanisms.

Mammalian X chromosome dosage compensation balances X-linked gene products between sexes and is coordinated by the long noncoding RNA (lncRNA) Xist. Multiple cis and trans-acting factors modulate Xist expression; however, the primary competence factor responsible for activating Xist remains a subject of dispute. The lncRNA Jpx is a proposed competence factor, yet it remains unknown if Jpx is sufficient to activate Xist expression in mice.

Transportin acts to regulate mitotic assembly events by target binding rather than Ran sequestration.

The nuclear import receptors importin β and transportin play a different role in mitosis: both act phenotypically as spatial regulators to ensure that mitotic spindle, nuclear membrane, and nuclear pore assembly occur exclusively around chromatin. Importin β is known to act by repressing assembly factors in regions distant from chromatin, whereas RanGTP produced on chromatin frees factors from importin β for localized assembly. The mechanism of transportin regulation was unknown.