Compartmentation of the nucleolar processing proteins in the granular component is a CK2-driven process.

To analyze the compartmentation of nucleolar protein complexes, the mechanisms controlling targeting of nucleolar processing proteins onto rRNA transcription sites has been investigated. We studied the reversible disconnection of transcripts and processing proteins using digitonin-permeabilized cells in assays capable of promoting nucleolar reorganization. The assays show that the dynamics of nucleolar reformation is ATP/GTP-dependent, sensitive to temperature, and CK2-driven.

Dynamics and compartmentation of the nucleolar processing machinery.

In active nucleoli, machineries involved in the biogenesis of ribosomal RNAs (rRNAs) are compartmentalized. The late rRNA processing proteins are localized in the granular component (GC). Here we investigate the behavior of these proteins when production of 28S is impaired and when this blockage is reversed.

3-D organization of ribosomal transcription units after DRB inhibition of RNA polymerase II transcription.

In each bead of the nucleolar necklace, using adenosine analog DRB-treated PtK1 cells, we investigated the three components of rDNA transcription, i.e. the gene, transcription factor UBF and transcripts.

Involvement of in situ conformation of ribosomal genes and selective distribution of upstream binding factor in rRNA transcription.

The distribution of the ribosomal genes (rDNA) and the upstream binding factor (UBF), correlatively with their RNA transcripts, was investigated in G1, S-phase, and G2. rDNA was distributed in nucleoli, with alternate sites of clustered and dispersed genes. UBF was found associated with some but not all clustered genes and proportionally more with dispersed genes.

The three-dimensional organization of ribosomal genes and the architecture of the nucleoli vary with G1, S and G2 phases.

The three-dimensional (3-D) organization of the nucleolus, a defined nuclear territory containing tandem repeats of the ribosomal genes (rDNA), was investigated in PtK1 cells. Identification of the interphase stages was performed in single cells using DNA quantification by cytometry for the G1 and G2 phases while the S phase was identified by immunolabelling of the proliferating cell nuclear antigen (PCNA). The 3-D organization of the rDNA in the nucleolus was analyzed by fluorescence in situ hybridization using confocal microscopy.

Three-dimensional organization of the ribosomal genes and Ag-NOR proteins during interphase and mitosis in PtK1 cells studied by confocal microscopy.

The three-dimensional (3-D) organization of rDNA-containing chromatin and the set of protein markers of active ribosomal genes, the Ag-NOR proteins, were investigated by confocal laser scanning microscopy (CLSM). The rDNA genes of marsupial cells (PtK1) were mapped using biotinylated DNA probes for 45S rDNA sequences and the Ag-NOR protein distribution was revealed by specific Ag-NOR staining. We used PtK1 cells because each nucleolus possesses only one nucleolar organizer region (NOR).

Characterization and hormonal regulation of tissue and fluid proteins in the mouse epididymis.

The proteins of epididymal tissues and fluids recovered from different regions of the mouse epididymis from a natural population and an inbred line were examined by polyacrylamide gel electrophoresis under denaturing conditions. Two epididymal specific peptides on the order of 88 and 20 Kilodaltons (Kd), undetected in serum and testicular extracts, were identified in the initial segment, caput, corpus and cauda. Another specific 30 Kd peptide was localized in the cauda tissue and fluid.

Characterization of regional proteins in tissues and fluids in the human epididymis.

The proteins of epididymal tissues and fluids recovered from five regions of the human epididymis were separated by polyacrylamide gel electrophoresis under denaturing conditions. Among the 60 peptides identified, eight appeared to be expressed solely in the epididymal duct when compared to serum and testis proteins. Three of these (92, 47 and 24 Kd) showed a degree of regional specificity in fluids.

[Hormonal control of vitellogenin synthesis in the Amphipoda Crustacea Orchestia gammarella (Pallas)].

The presence of a vitellogenin stimulating ovarian hormone (VSOH) in Orchestia gammarella has been demonstrated by gonadectomy and ovary grafting. Vitellogenin synthesis is not affected by molting hormone injection; it decreases after Y-organ (molting gland) cauterization. Studies in progress seem to indicate that the destruction of the median area of the protocerebrum is followed by a decrease of this synthesis.

[Molecular weight of lipovitellins during egg development in the crustacean amphipod Orchestia gammarella (Pallas)].

Egg lipovitellins of Orchestia gammarella tested by electrophoresis on gels of different acrylamide concentrations, following the procedure of Hedrick and Smith (1968), display a migration pattern identical to that of proteins with molecular weights of congruent to 3.2 x 10(5) (lipovitellin I) and congruent to 5.5 x 10(5) (lipovitellin II) respectively.

[Determination of the molecular weight of vitellogenin and of lipovitellins of Orchestia gammarella, Crustacea, Amphipoda].

Vitellogenin and lipovitellins of Orchestia gammarella, tested by electrophoresis on gels of different acrylamide concentrations, following the procedure of Hedrick and Smith (1968), displays a migration pattern identical to that of proteins of respectively congruent to 4 x 10(5) (vitellogenin), congruent to 3,5 x 10(5) (lipovitellins I and I') and congruent to 5 x 10(5) (lipovitellin II) molecular weights.

[Molting and vitellogenesis in Orchestia gammarella Pallas (crustacea amphipoda): study of the female-specific protein synthesis after ecdysterone administration (author's transl)].

Ecdysterone, administered to Orchestia gammarella females (200 mug/g), has no positive effect on the female-specific protein synthesis and vitellogenesis.