Live-cell imaging of the nucleolus and mapping mitochondrial viscosity with a dual function fluorescent probe

One probe but two targets: viscous mitochondria to nucleolar staining.

A cationic organoiridium(iii) complex-based AIEgen for selective light-up detection of rRNA and nucleolar staining

Cyclometalated Ir(iii) complex-based AIEgen has been developed to selectively detect and stain the cell rRNA which has been revealed by in vitro PL studies and cell imaging experiment.

Catalytic Subunit of Human Telomerase Reverse Transcriptase Is an Independent Predictor of Survival in Patients Undergoing Curative Resection of Hepatic Colorectal Metastases: A Multicenter Analysis

Purpose To determine the role of the catalytic subunit of human telomerase reverse transcriptase (hTERT) in predicting survival after resection of hepatic colorectal metastases (CRM). Patients and Methods Two hundred one patients who underwent curative resection of hepatic CRM between 1990 and 2000 were identified from a multicenter database. The CRM were analyzed for hTERT nucleolar expression by standard immunohistochemical techniques. hTERT expression and known clinicopathologic factors of survival were examined. Results With a median follow-up of 80 months, 152 patients (75.6%) had died; the 5-year overall survival was 30.7%. On univariate analysis, number of metastases greater than two (P = .0005), extrahepatic disease (P = .0054), disease-free interval less than 12 months (P = .006), carcinoembryonic antigen level greater than 200 ng/mL (P = .0071), and positive hTERT nucleolar staining (P < .0001) were associated with decreased survival. On multivariate analysis, three factors independently predicted survival: number of metastases (relative risk [RR] = 1.74; P = .0011); disease-free interval (RR = 1.70; P = .0035); and positive hTERT nucleolar staining (RR = 2.03; P < .0001). Patients with none or one of these factors had a 5-year survival rate of 48%, whereas those with two or three of these factors had a 5-year survival of 15% (P < .0001). Conclusion hTERT nucleolar expression is associated with worse survival after resection of hepatic CRM. hTERT expression in conjunction with number of hepatic metastases and disease-free interval may permit more accurate prediction of survival after resection of hepatic CRM.

Transient Nucleolar Localization Of U6 Small Nuclear RNA InXenopus Laevis Oocytes

Recent studies on the 2′-O-methylation and pseudouridylation of U6 small nuclear RNA (snRNA) hypothesize that these posttranscriptional modifications might occur in the nucleolus. In this report, we present direct evidence for the nucleolar localization of U6 snRNA and analyze the kinetics of U6 nucleolar localization after injection of in vitro transcribed fluorescein-labeled transcripts into Xenopus laevis oocytes. In contrast to U3 small nucleolar RNA (snoRNA) which developed strong nucleolar labeling over 4 h and maintained strong nucleolar signals through 24 h, U6 snRNA localized to nucleoli immediately after injection, but nucleolar staining decreased after 4 h. By 24 h after injection of U6 snRNA, only weak nucleolar signals were observed. Unlike the time-dependent profile of strong nucleolar localization of U6 snRNA or U3 snoRNA, injection of fluorescein-labeled U2 snRNA gave weak nucleolar staining at all times throughout a 24-h period; U2 snRNA modifications are believed to occur outside of the nucleolus. The notion that the decrease of U6 signals over time was due to its trafficking out of nucleoli and not to transcript degradation was supported by the demonstration of U6 snRNA stability over time. Therefore, in contrast to snoRNAs like U3, U6 snRNA transiently passes through nucleoli.

Microsporogenesis and gametophyte maturation in cultured tassels of Zea mays

Normal meiosis and pollen maturation occurred in vitro in anthers of cultured tassels of Zea mays L. (cv. Seneca-60). The meiotic figures observed in propiocarmine squashes of these anthers were comparable to those of anthers which developed in situ, not only in terms of the end product, pollen, but also in the intermediate stages. Meiotic prophase stages, quartets and microspores, and binucleate pollen regularly appeared within 7, 10, and 14 days of culture, respectively. This timing was 3–4 days behind that found in situ. Cytoplasmic and nucleolar staining, chromosomal configurations, and cell size were similar to that found in situ.

Use of monoclonal antibodies for the characterization of novel DNA-binding proteins recognized by human autoimmune sera.

Autoantibodies to a DNA-binding heterodimer consisting of 70,000 and 80,000 dalton subunits were identified in 30-50% of human autoimmune sera from patients with systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), and scleroderma. Three murine monoclonal antibodies (mAb) against the heterodimer were produced in BALB/c mice by immunizing with isolated human B cell nuclei. By immunofluorescence, the mAb and autoimmune sera demonstrated both speckled nucleoplasmic staining and diffuse nucleolar staining in all human cell types examined. The nucleoplasmic staining was sensitive to DNase but not RNase pretreatment, while the nucleolar staining was sensitive to RNase but not DNase pretreatment. Biochemical characterization of the 70,000 and 80,000 dalton proteins using the mAb indicated that two forms of the antigen, with different mobilities on sucrose gradients, are present in human B cells. A 10 S form consists of the physically associated 70,000 and 80,000 dalton proteins, while a larger, 10-20 S form probably represents the same two proteins bound to DNA. Binding of the proteins to nucleolar RNA could not be confirmed in biochemical studies. These studies indicate that non-histone, DNA-binding proteins may be more frequently recognized by autoantibodies in SLE, MCTD, and scleroderma than has been previously recognized. Along with previous studies on RNA-binding proteins such as Sm, RNP, Ro, and La, the present findings suggest that nucleic acid-binding proteins, as a class, may be particularly frequent targets of autoimmunity in SLE and related disorders.