Related Experiment Video
Updated: May 29, 2026
Experimental Design for Laser Microdissection RNA-Seq: Lessons from an Analysis of Maize Leaf Development
Published on: March 5, 2017
mRNA accumulation in the Cajal bodies of the diplotene larch microsporocyte
Dariusz Jan Smoliński1, Agnieszka Kołowerzo
1Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100 Toruń, Poland. darsmol@uni.torun.pl
Abstract:
In microsporocytes of the European larch, we demonstrated the presence of several mRNAs in spherical nuclear bodies. In the nuclei of microsporocytes, we observed up to 12 bodies, ranging from 0.5 to 6 μm in diameter, during the prophase of the first meiotic division. Our previous studies revealed the presence of polyadenylated RNA (poly(A) RNA) in these bodies, but did not confirm the presence of nascent transcripts or splicing factors of the SR family. The lack of these molecules precludes the bodies from being the sites of synthesis and early maturation of primary transcripts (Kołowerzo et al., Protoplasma 236:13-19, 2009). However, the bodies serve as sites for the accumulation of splicing machinery, including the Sm proteins and small nuclear RNAs. Characteristic ultrastructures and the molecular composition of the nuclear bodies, which contain poly(A) RNA, are indicative of Cajal bodies (CBs). Here, we demonstrated the presence of several housekeeping gene transcripts--α-tubulin, pectin methylesterase, peroxidase and catalase, ATPase, and inositol-3-phosphate synthase--in CBs. Additionally, we observed transcripts of the RNA polymerase II subunits RPB2 and RPB10 RNA pol II and the core spliceosome proteins mRNA SmD1, SmD2, and SmE. The co-localization of nascent transcripts and mRNAs indicates that mRNA accumulation/storage, particularly in CBs, occurs in the nucleus of microsporocytes.
Insights
Nuclear bodies in European larch microsporocytes store messenger RNAs (mRNAs). These Cajal bodies (CBs) accumulate various housekeeping and RNA polymerase II transcripts, indicating a role in nuclear mRNA storage.
Area of Science:
- Cell Biology
- Molecular Biology
- Plant Science
Background:
- Nuclear bodies in European larch microsporocytes were previously found to contain polyadenylated RNA (poly(A) RNA).
- These bodies were not confirmed to be sites of nascent transcript synthesis or early maturation due to the absence of SR splicing factors.
- The presence of Sm proteins and small nuclear RNAs suggested a role in splicing machinery accumulation.
Purpose of the Study:
- To investigate the molecular composition of nuclear bodies in European larch microsporocytes.
- To determine if these bodies function in mRNA accumulation or storage.
- To characterize the specific transcripts localized within these nuclear structures.
Main Methods:
- Microscopic observation of nuclear bodies in microsporocytes during meiotic prophase.
- Detection and localization of specific mRNAs using molecular techniques.
- Analysis of nuclear body ultrastructure and molecular composition.
Main Results:
- Nuclear bodies, identified as Cajal bodies (CBs), were observed in European larch microsporocytes.
- Transcripts for housekeeping genes (e.g., α-tubulin, ATPase) and RNA polymerase II subunits were found within CBs.
- Co-localization of nascent transcripts and mRNAs confirmed mRNA accumulation/storage within these nuclear bodies.
Conclusions:
- Nuclear bodies in European larch microsporocytes, identified as Cajal bodies, serve as sites for mRNA accumulation and storage.
- The presence of diverse transcripts indicates a significant role for these structures in nuclear mRNA management.
- This finding provides new insights into post-transcriptional regulation in plant microsporocytes.
