In genetic hybrids, nucleolus formation on chromosomes inherited from only one parent is the epigenetic phenomenon, nucleolar dominance. By using Arabidopsis suecica, the allotetraploid hybrid of Arabidopsis thaliana and Arabidopsis arenosa, natural variation in nucleolar dominance was found to occur, providing a unique opportunity to examine homologous nucleolus organizer regions (NORs) in the...

The nucleolus is a large nuclear domain generated by the act of building ribosomes. It illustrates the compartmentation of the nuclear functions, since it is in the nucleolus that transcription of the ribosomal genes, maturation and processing of the 47S ribosomal RNAs (rRNAs) into 18S, 5.8S and 28S rRNA, and almost complete assembly of the 40S and 60S ribosome subunits take place. The shape, s...

Both the Ku subunit of the DNA-dependent protein kinase (DNA-PK) and the facilitator of chromatin transcription (FACT) complex reportedly bind cisplatin-DNA adducts. For this study, we developed an immunocytochemical assay based on detergent extraction allowing unveiling nucleolar subpopulations of proteins present in both the nucleoplasm and the nucleolus. Immunofluorescence analysis in variou...

Background:The nucleolinus is a little known cellular structure associated with the nucleolus that was discovered over 150 years ago. Results: It contains a unique set of molecules associated with cell division. Conclusion: Combined with laser microsurgery experiments, the observations suggest a role for the nucleolinus in spindle formation. Significance: The nucleolinus appears to be a tangibl...

Electron-microscope observations indicate that the single nuclear division of sporulating yeasts which form 2-spored asci resembles, in several aspects, the nuclear behaviour during sporulation of the more common 4-spored yeasts. Specifically the parental nucleolus remains behind in the ascus cytoplasm, a characteristic nucleolus-associatcd spherical structure is formed, and the nucleus divides...

An enzymatic maceration and Giemsa staining method was used to compare the karyotypes of Crotalaria laburnifolia (trifoliate) C. spectabilis (simple leaves) species belonging distinct morphological sections with different degrees floral specialization. Both taxa share a 2n=16, asymmetric chromosome complement, relatively similar karyotypic formulae. However, differences in chromosome-SAT, sizes...

SUMMARY Arabidopsis thaliana 45S ribosomal genes (rDNA) are located in tandem arrays called nucleolus organizing regions on the termini of chromosomes 2 and 4 (NOR2 NOR4) encode rRNA, a crucial structural element ribosome. The current model rDNA organization suggests that inactive rRNA accumulate condensed chromocenters nucleus at nucleolar periphery, while delineates active genes. We challenge...

In some situations, sellers of certain commodities usually provide price discounts for large orders according to a decreasing unit function. Buyers such can cooperate and form purchasing groups benefit from these discounts. A natural way allocate the corresponding cost reductions is equal rule. We analyze this situation as cooperative game. show that when function linear, rule coincides with Sh...