Coiled bodies in nuclei from plant cells evolving from dormancy to proliferation

Abstract

To characterise the coiled bodies in meristematic nuclei of Saccharum officinarum, immunofluorescence labelling with antibodies against components of the splicing (U2B'' and Sm core protein B) and pre-rRNA processing (fibrillarin) complexes was used in cells from the dormant root primordia and from roots at different times after activation to the steady state of proliferation. The number, size and distribution of coiled bodies varied in the meristematic tissue depending on cell activity. While G0 cells in the dry primordia and proliferating cells showed a similar number of coiled bodies attached to their nucleoli, the number of nucleoplasmic coiled bodies greatly increased after the primordia were stimulated to proliferate. Their number remained steady from the time the meristematic population reached the steady state of proliferation, as estimated by flow cytometry. Fractionation studies demonstrated that coiled bodies are a part of the underlying nuclear matrix. Comparison of immunocytochemical and cytochemical data from confocal and electron microscopical studies demonstrated that the nucleolar and nucleoplasmic coiled bodies detected by confocal microscopy shared many features, suggesting that they form a family of closely related structures.

Tissue-specific Expression and Dynamic Organization of SR Splicing Factors inArabidopsis

“…Nuclear compartmentalization is thought to facilitate the regulation of transcription and pre-mRNA splicing to generate mature transcripts (Lamond and Earnshaw, 1998). However, the presence of IGCs in plant nuclei has not been previously identified (Testillano et al, 1993;Acevedo et al, 2002;Cui and Moreno Díaz de la Espina, 2003;Docquier et al, 2004). Our observations demonstrated that two SF2/ASF and one SC35-like splicing factor localize to speckles that correspond to IGCs in plant nuclei upon TEM analysis.…”

“…In plants, spliceosomal components were found to localize in Cajal bodies (Beven et al, 1995;Boudonck et al, 1998Boudonck et al, , 1999Acevedo et al, 2002;Cui and Moreno Díaz de la Espina, 2003;Docquier et al, 2004) and in nuclear speckles (Lopato et al, 2002;Ali et al, 2003;Docquier et al, 2004). However, only the plant-specific SR proteins were studied in living cells from a limited number of cell types, and the expression of green fluorescent protein-tagged SR proteins were under the control of a highly active constitutive 35S promoter (Lopato et al, 2002;Ali et al, 2003;Docquier et al, 2004).…”

“…Furthermore, members of a plant-specific family of SR proteins termed the atRSp31 family (atRSp31, atRSp40, and atRSp41) were isolated (Lopato et al, 1996). More recently, a plant-specific SR protein atRSZ33 was shown to interact with SR1/atSRp34, atRSZp21, atSRZp22 and SC35-like splicing factors (Lopato et al, 2002).In plants, spliceosomal components were found to localize in Cajal bodies (Beven et al, 1995;Boudonck et al, 1998Boudonck et al, , 1999Acevedo et al, 2002;Cui and Moreno Díaz de la Espina, 2003;Docquier et al, 2004) and in nuclear speckles (Lopato et al, 2002;Ali et al, 2003;Docquier et al, 2004). However, only the plant-specific SR proteins were studied in living cells from a limited number of cell types, and the expression of Article published online ahead of print.…”

Behaviour of ribosomal genes and nucleolar domains during activation in sugarcane (Saccharum officinarum L.) root primordia: from the unsoaked quiescent state to the steady state of proliferation

“…Cellular preparations were air-dried and kept at -20ºC until use. After quenching aldehyde groups with a freshly prepared 1mg/ml NaBH 4 solution in PBS pH 8.0, 3x15 min, the slides were blocked and incubated with the primary and secondary antibodies as previously described (Acevedo et al, 2002). Experiments omitting the incubation with the primary antibody were performed as negative controls.…”

“…The nucleolus is also involved in cell activities not related with ribosome biogenesis, as the assembly and processing of small RNP particles like the signal recognition particle (SRP), telomerase, U6 splicing particle and tRNA particles (Pederson, 1998;Olson et al, 2000). Some of these functions appear to be related with the nucleolus-associated Cajal's bodies (CBs: Olson et al, 2000;Acevedo et al, 2002).…”