Nucleolin and Nucleophosmin Expression in Gleason 3 and Gleason 4 Prostate Cancer With Seminal Vesicles Invasion (pT3b)

BACKGROUND/AIM

The aim of this study was to analyze the expression of nucleolin (NCL) and nucleophosmin (NPM) in prostate adenocarcinoma and in its loco-regional spread in the form of seminal vesicle invasion (SVI).

MATERIALS AND METHODS

The study was performed on tissue microarrays of 40 cases of Gleason 3+4 pT3b prostate cancers including tissue samples from SVI. The expression of NCL and NPM was detected immunohistochemically and analyzed with image analysis software.

RESULTS

The expression of NCL and NPM were higher in cancer cells within a prostate gland than in SVI. Gleason 4 pattern showed higher expression of NPM than Gleason 3 pattern cells.

CONCLUSION

Differences in nuclear NCL and NPM expression in cancer cells between the prostate gland and SVI may indicate involvement of these proteins in loco-regional spread of adenocarcinoma of the prostate. Differences in NPM expression in Gleason 3 and Gleason 4 pattern suggest involvement of this protein in the differentiation of prostate cancer.

Evolution of the Sex Chromosomes in Beetles. I. The Loss of the Y Chromosome

In the males of Coleoptera, the most frequent sex chromosome constitution is XY. At metaphase I of meiosis, the X and Y are linked by nucleolar proteins, forming the so-called parachute bivalent (Xyp), which is assumed to allow the non-synapsed X and Y to segregate correctly at anaphase I. However, X0 males are not exceptional, and we explored the relationships between the X and nucleolar proteins in the absence of the Y chromosome in 6 species belonging to different families/subfamilies. Using C-banding and silver staining, we show that nucleolar proteins always remain in contact with the X until anaphase I. These proteins are generally more abundant than in the Xyp bivalent, may remain associated with the NOR during diakinesis, and frequently link the X to 1 or 2 autosomal bivalents, which seem to play the same role as the Y. This role may also be played by B chromosomes, which appear to be more frequent in X0 than in XY males. In conclusion, following Y chromosome loss, various strategies using nucleolar proteins have been developed to facilitate the migration of the unique X at meiotic anaphase I.

High-resolution microscopy of active ribosomal genes and key members of the rRNA processing machinery inside nucleolus-like bodies of fully-grown mouse oocytes

Nucleolus-like bodies (NLBs) of fully-grown (germinal vesicle, GV) mammalian oocytes are traditionally considered as morphologically distinct entities, which, unlike normal nucleoli, contain transcribed ribosomal genes (rDNA) solely at their surface. In the current study, we for the first time showed that active ribosomal genes are present not only on the surface but also inside NLBs of the NSN-type oocytes. The "internal" rRNA synthesis was evidenced by cytoplasmic microinjections of BrUTP as precursor and by fluorescence in situ hybridization with a probe to the short-lived 5'ETS segment of the 47S pre-rRNA. We further showed that in the NLB mass of NSN-oocytes, distribution of active rDNA, RNA polymerase I (UBF) and rRNA processing (fibrillarin) protein factors, U3 snoRNA, pre-rRNAs and 18S/28S rRNAs is remarkably similar to that in somatic nucleoli capable to make pre-ribosomes. Overall, these observations support the occurrence of rDNA transcription, rRNA processing and pre-ribosome assembly in the NSN-type NLBs and so that their functional similarity to normal nucleoli. Unlike the NSN-type NLBs, the NLBs of more mature SN-oocytes do not contain transcribed rRNA genes, U3 snoRNA, pre-rRNAs, 18S and 28S rRNAs. These results favor the idea that in a process of transformation of NSN-oocytes to SN-oocytes, NLBs cease to produce pre-ribosomes and, moreover, lose their rRNAs. We also concluded that a denaturing fixative 70% ethanol used in the study to fix oocytes could be more appropriate for light microscopy analysis of nucleolar RNAs and proteins in mammalian fully-grown oocytes than a commonly used cross-linking aldehyde fixative, formalin.

Nucleolus-like bodies of fully-grown mouse oocytes contain key nucleolar proteins but are impoverished for rRNA

It is well known that fully-grown mammalian oocytes, rather than typical nucleoli, contain prominent but structurally homogenous bodies called "nucleolus-like bodies" (NLBs). NLBs accumulate a vast amount of material, but their biochemical composition and functions remain uncertain. To clarify the composition of the NLB material in mouse GV oocytes, we devised an assay to detect internal oocyte proteins with fluorescein-5-isothiocyanate (FITC) and applied the fluorescent RNA-binding dye acridine orange to examine whether NLBs contain RNA. Our results unequivocally show that, similarly to typical nucleoli, proteins and RNA are major constituents of transcriptionally active (or non-surrounded) NLBs as well as of transcriptionally silent (or surrounded) NLBs. We also show, by exposing fixed oocytes to a mild proteinase K treatment, that the NLB mass in oocytes of both types contains nucleolar proteins that are involved in all major steps of ribosome biogenesis, including rDNA transcription (UBF), early rRNA processing (fibrillarin), and late rRNA processing (NPM1/nucleophosmin/B23, nucleolin/C23), but none of the nuclear proteins tested, including SC35, NOBOX, topoisomerase II beta, HP1α, and H3. The ribosomal RPL26 protein was detected within the NLBs of NSN-type oocytes but is virtually absent from NLBs of SN-type oocytes. Taking into account that the major class of nucleolar RNA is ribosomal RNA (rRNA), we applied fluorescence in situ hybridization with oligonucleotide probes targeting 18S and 28S rRNAs. The results show that, in contrast to active nucleoli, NLBs of fully-grown oocytes are impoverished for the rRNAs, which is consistent with the absence of transcribed ribosomal genes in the NLB mass. Overall, the results of this study suggest that NLBs of fully-grown mammalian oocytes serve for storing major nucleolar proteins but not rRNA.