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Shedding light on paraspeckle structure by super-resolution microscopy

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ABSTRACT

The nuclear body paraspeckle is built on the lncRNA Neat1 and plays important roles in gene regulation. In this issue, West et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201601071) use super-resolution structured illumination microscopy to show that paraspeckles are organized in a core-shell spheroidal structure composed of Neat1 and seven proteins.

No MeSH data available.


A schematic drawing shows the transverse section of the core-shell spheroid paraspeckle structure. Under SIM, the paraspeckle structure can be divided into two parts, the core and the shell. The core of paraspeckles contains the middle region of Neat1_2 (shown as Neat1_mid) and proteins SFPQ, PSPC1, NONO, and FUS. The 5′ and 3′ ends of Neat1_2 (shown as Neat1_5′+3′) and the protein TDP43 are located in the shell of paraspeckles. Proteins RBM14 and BRG1, defined by West et al. (2016) as patch proteins, are located in both the core and the shell of paraspeckles. FUS proteins assemble the paraspeckle-like core units and patch/shell proteins into paraspeckle spheroids. The AG-rich RNAs are enriched in the surface of paraspeckles, whereas the previously reported inverted repeats containing mRNAs interact with the core proteins and are proposed to localize in the middle of paraspeckles.
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fig1: A schematic drawing shows the transverse section of the core-shell spheroid paraspeckle structure. Under SIM, the paraspeckle structure can be divided into two parts, the core and the shell. The core of paraspeckles contains the middle region of Neat1_2 (shown as Neat1_mid) and proteins SFPQ, PSPC1, NONO, and FUS. The 5′ and 3′ ends of Neat1_2 (shown as Neat1_5′+3′) and the protein TDP43 are located in the shell of paraspeckles. Proteins RBM14 and BRG1, defined by West et al. (2016) as patch proteins, are located in both the core and the shell of paraspeckles. FUS proteins assemble the paraspeckle-like core units and patch/shell proteins into paraspeckle spheroids. The AG-rich RNAs are enriched in the surface of paraspeckles, whereas the previously reported inverted repeats containing mRNAs interact with the core proteins and are proposed to localize in the middle of paraspeckles.

Mentions: A previous study of paraspeckles by electron microscopy showed that both Neat1 isoforms (the less abundant long isoform Neat1_2, which is essential for paraspeckle construction, and the abundant, shorter isoform Neat1_1, which seems dispensable for paraspeckle assembly) are found at the periphery of paraspeckles, with the central sequence of the Neat1_2 (Neat1_mid) isoform located in the core of paraspeckles (Souquere et al., 2010; Fig. 1). West et al. (2016) designed three probes that individually recognize the 5′ end, the middle, or the 3′ end of Neat1_2 to visualize paraspeckles using RNA fluorescence in situ hybridization under SIM. SIM observations of the combination of these probes for Neat1_2 revealed a core-shell spheroidal arrangement of Neat1_2 (Fig. 1). Consistent with previous electron microscopy observations (Souquere et al., 2010), the middle region of Neat1_2 formed a solid core that was surrounded by its 5′ and 3′ ends, supporting the hypothesis that SIM is appropriate to visualize paraspeckles in super-resolution. Notably, the majority of paraspeckles appeared as disperse spheroids, whereas a small proportion dimerized and even polymerized to form sausage-like structures.


Shedding light on paraspeckle structure by super-resolution microscopy
A schematic drawing shows the transverse section of the core-shell spheroid paraspeckle structure. Under SIM, the paraspeckle structure can be divided into two parts, the core and the shell. The core of paraspeckles contains the middle region of Neat1_2 (shown as Neat1_mid) and proteins SFPQ, PSPC1, NONO, and FUS. The 5′ and 3′ ends of Neat1_2 (shown as Neat1_5′+3′) and the protein TDP43 are located in the shell of paraspeckles. Proteins RBM14 and BRG1, defined by West et al. (2016) as patch proteins, are located in both the core and the shell of paraspeckles. FUS proteins assemble the paraspeckle-like core units and patch/shell proteins into paraspeckle spheroids. The AG-rich RNAs are enriched in the surface of paraspeckles, whereas the previously reported inverted repeats containing mRNAs interact with the core proteins and are proposed to localize in the middle of paraspeckles.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5037413&req=5

fig1: A schematic drawing shows the transverse section of the core-shell spheroid paraspeckle structure. Under SIM, the paraspeckle structure can be divided into two parts, the core and the shell. The core of paraspeckles contains the middle region of Neat1_2 (shown as Neat1_mid) and proteins SFPQ, PSPC1, NONO, and FUS. The 5′ and 3′ ends of Neat1_2 (shown as Neat1_5′+3′) and the protein TDP43 are located in the shell of paraspeckles. Proteins RBM14 and BRG1, defined by West et al. (2016) as patch proteins, are located in both the core and the shell of paraspeckles. FUS proteins assemble the paraspeckle-like core units and patch/shell proteins into paraspeckle spheroids. The AG-rich RNAs are enriched in the surface of paraspeckles, whereas the previously reported inverted repeats containing mRNAs interact with the core proteins and are proposed to localize in the middle of paraspeckles.
Mentions: A previous study of paraspeckles by electron microscopy showed that both Neat1 isoforms (the less abundant long isoform Neat1_2, which is essential for paraspeckle construction, and the abundant, shorter isoform Neat1_1, which seems dispensable for paraspeckle assembly) are found at the periphery of paraspeckles, with the central sequence of the Neat1_2 (Neat1_mid) isoform located in the core of paraspeckles (Souquere et al., 2010; Fig. 1). West et al. (2016) designed three probes that individually recognize the 5′ end, the middle, or the 3′ end of Neat1_2 to visualize paraspeckles using RNA fluorescence in situ hybridization under SIM. SIM observations of the combination of these probes for Neat1_2 revealed a core-shell spheroidal arrangement of Neat1_2 (Fig. 1). Consistent with previous electron microscopy observations (Souquere et al., 2010), the middle region of Neat1_2 formed a solid core that was surrounded by its 5′ and 3′ ends, supporting the hypothesis that SIM is appropriate to visualize paraspeckles in super-resolution. Notably, the majority of paraspeckles appeared as disperse spheroids, whereas a small proportion dimerized and even polymerized to form sausage-like structures.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

The nuclear body paraspeckle is built on the lncRNA Neat1 and plays important roles in gene regulation. In this issue, West et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201601071) use super-resolution structured illumination microscopy to show that paraspeckles are organized in a core-shell spheroidal structure composed of Neat1 and seven proteins.

No MeSH data available.