Nucleolus Organizer Regions in Mitotic Chromosomes of the Domestic Horse

Ribosomal Rna in the Nucleolus Organizer

Occurrence of multiple nucleolus organizer regions and intraspecific karyotype variation in Scaptotrigona xanthotricha Moure (Hymenoptera, Meliponini).

Scaptotrigona xanthotricha has a wide geographic distribution in the Brazilian Atlantic rainforest. One population from southeast and two from northeast Brazil were analyzed and were found to have chromosome polymorphisms. Although the chromosome number 2n = 34 is conserved in this species, karyotypic analysis revealed clear differences between the three populations. Congruent and ubiquitous mu...

Revealing the unseen: the organizer region of the nucleolus.

We carried out a high-resolution ultrastructural analysis of the nucleolus in mouse P815 cells by combining specific DNA and RNA staining, anti-fibrillarin immunolabeling, contrast enhancement by energy filtering TEM and phosphorus mapping by ESI to visualize nucleic acids. We demonstrated that specifically contrasted DNA, fibrillarin and phosphorus overlap within the nucleolar dense fibrillar ...

Evidence for nucleolus organizer regions as the units of regulation in nucleolar dominance in Arabidopsis thaliana interecotype hybrids.

Nucleolar dominance describes the silencing of one parent's ribosomal RNA (rRNA) genes in a genetic hybrid. In Arabidopsis thaliana, rRNA genes are clustered in two nucleolus organizer regions, NOR2 and NOR4. In F(8) recombinant inbreds (RI) of the A. thaliana ecotypes Ler and Cvi, lines that display strong nucleolar dominance inherited a specific combination of NORs, Cvi NOR4 and Ler NOR2. The...

Holocentric chromosomes of Luzula elegans are characterized by a longitudinal centromere groove, chromosome bending, and a terminal nucleolus organizer region.

The structure of holocentric chromosomes was analyzed in mitotic cells of Luzula elegans. Light and scanning electron microscopy observations provided evidence for the existence of a longitudinal groove along each sister chromatid. The centromere-specific histone H3 variant, CENH3, colocalized with this groove and with microtubule attachment sites. The terminal chromosomal regions were CENH3-ne...