Biology subjects

Kurosaka, S.

Publications and source records attributed to Kurosaka, S..

3 recordsLinked to original sources

bioRxiv2022

Species-Specific Formation of Paraspeckles in Intestinal Epithelium Revealed by Characterization of NEAT1 in Naked Mole-rat

Paraspeckles are mammalian-specific nuclear bodies built on the long noncoding RNA NEAT1_2. The molecular mechanisms of paraspeckle formation have been mainly studied using human or mouse cells, and it is not known if the same molecular components are involved in the formation of paraspeckles in other mammalian species. We thus investigated the expression pattern of NEAT1_2 in naked mole-rats (nNEAT1_2), which exhibit extreme longevity and lower susceptibility to cancer. In the intestine, nNEAT1_2 is widely expressed along the entire intestinal epithelium, which is different from the expression of mNeat1_2, that is restricted to the cells of the distal tip in mice. Notably, the expression of FUS, a FET family RNA binding protein, essential for the formation of paraspeckles both in humans and mice, was absent in the distal part of the intestinal epithelium in naked mole-rats. Instead, mRNAs of other FET family proteins EWSR1 and TAF15 were expressed in the distal region. Exogenous expression of these proteins in Fus-deficient murine embryonic fibroblast cells rescued the formation of paraspeckles. These observations suggest that nNEAT1_2 recruits different set of RNA binding proteins in a cell type-specific manner during the formation of paraspeckles in different organisms.

molecular biology↗

bioRxiv2021

Different translation dynamics of β- and γ-actin regulates cell migration

{beta}- and {gamma}-cytoplasmic actins are ubiquitously expressed in every cell type and are nearly identical at the amino acid level but play vastly different roles in vivo. Their essential roles in embryogenesis and cell migration critically depend on the nucleotide sequences of their genes, rather than their amino acid sequence. However it is unclear which gene elements underlie this effect. Here we address the specific role of the coding sequence in {beta}- and {gamma}-cytoplasmic actins intracellular functions, using stable cell lines with exogenously expressed actin isoforms and their "codon-switched" variants. When targeted to the cell periphery using the {beta}-actin 3'UTR, {beta}-actin and {gamma}-actin have differential effects on cell migration. These effects directly depend on the coding sequence. Single molecule measurements of actin isoform translation, combined with fluorescence recovery after photobleaching, demonstrate a pronounced difference in {beta}- and {gamma}-actins translation elongation rates, leading to changes in their dynamics at focal adhesions, impairments in actin bundle formation, and reduced cell anchoring to the substrate during migration. Our results demonstrate that coding sequence-mediated differences in actin translation play a key role in cell migration.

cell biology↗

bioRxiv2017

Diverse functions of closely homologous actin isoforms are defined by their nucleotide, rather than their amino acid sequence.

{beta}- and {gamma}-cytoplasmic-actin are nearly indistinguishable in their amino acid sequence, but are encoded by different genes that play non-redundant biological roles. The key determinants that drive their functional distinction are unknown. Here we tested the hypothesis that {beta}- and {gamma}-actin functions are defined by their nucleotide, rather than their amino acid sequence, using targeted editing of the mouse genome. Although previous studies have shown that disruption of {beta}-actin gene critically impacts cell migration and mouse embryogenesis, we demonstrate here that generation of a mouse lacking {beta}-actin protein by editing {beta}-actin gene to encode {gamma}-actin protein, and vice versa, does not affect cell migration and/or organism survival. Our data suggest that the essential in vivo function of {beta}-actin is provided by the gene sequence independent of the encoded protein isoform. We propose that this regulation constitutes a global \"silent code\" mechanism that controls the functional diversity of protein isoforms.

cell biology↗