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Updated: Jun 23, 2026
Analysis of Spliceosomal snRNA Localization in Human Hela Cells Using Microinjection
Published on: August 6, 2019
Poly(A) RNA a new component of Cajal bodies
Agnieszka Kołowerzo1, Dariusz Jan Smoliński, Elzbieta Bednarska
1Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, Toruń, 87-100, Poland.
Abstract:
In European larch microsporocytes, spherical structures 0.5 to 6 microm in diameter are present in which poly(A) RNA accumulates. There were one to several bodies per cell and they were often present in the vicinity of the nucleolus. No nascent transcripts were observed within them. Splicing factors of the SR family, including protein SC35, which participates in bringing the 3' and 5' sites closer in the splicing reaction, were also not observed. The absence of the above-mentioned elements within bodies containing poly(A) RNA disqualifies them as sites of synthesis and preliminary stages of primary transcript maturation. However, they contained abundant elements of the splicing machinery commonly occurring in Cajal bodies, i.e., Sm proteins or small nuclear RNA (snRNA). The molecular composition as well as the characteristic ultrastructure of bodies containing poly(A) RNA proves that these were Cajal bodies. This is the first report of such poly(A) RNA localization.
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