objective: breast cancer comprise approximately one third of malignant cases in women and is considered as the most common invasive condition in women at an age range of 15-54 years and as the second most prevalent cause of mortality at an age range of 55-74 years. tumor inhibiting factor p53 is a vital homeostatic regulator and its inactivation at the related gene or molecule could lead to tum...

Objective: Breast cancer comprise approximately one third of malignant cases in women and is considered as the most common invasive condition in women at an age range of 15-54 years and as the second most prevalent cause of mortality at an age range of 55-74 years. Tumor inhibiting factor p53 is a vital ...

The number and volume of fibrillar centres, the structural components of interphase cell nucleoli on the surface of which rRNA is synthesized, have been studied in differentiating erythroblasts of mouse embryo liver. Complete series of ultrathin sections of erythroblast nuclei have been used at the main stages of differentiation: proerythroblast, basophilic erythroblast, polychromatophilic eryt...

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...

How the nucleolus is segregated during mitosis is poorly understood and occurs by very different mechanisms during closed and open mitosis. Here we report a new mechanism of nucleolar segregation involving removal of the nucleolar-organizing regions (NORs) from nucleoli during Aspergillus nidulans mitosis. This involves a double nuclear envelope (NE) restriction which generates three NE-associa...

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...

During the endopolyploidization of the suspensor cells of Phaseolus coccineus and P. vulgaris, polytene chromosomes and an important nucleolar apparatus develop within the nuclei. The nucleolus-associated regions of the four nucleolus-organizing chromosomes and the regions of the secondary constrictions (intranucleolar chromatin threads) show a temperature-dependent, reversible variability in t...