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Identification of a small, very acidic constitutive nucleolar protein (NO29) as a member of the nucleoplasmin family.

ABSTRACT: We report the discovery and molecular characterization of a small and very acidic nucleolar protein of an SDS/PAGE mobility corresponding to Mr 29,000 (NO29). The cDNA-deduced sequence of the Xenopus laevis protein defines a polypeptide of a calculated molecular mass of 20,121 and a pI of 3.75, with an extended acidic region near its C terminus, and is related to the major nucleolar protein, NO38, and the histone-binding protein, nucleoplasmin. This member of the nucleoplasmin family of proteins was immunolocalized to nucleoli in Xenopus oocytes and diverse somatic cells. Protein NO29 is associated with nuclear particles from Xenopus oocytes, partly complexed with protein NO38, and occurs in preribosomes but not in mature ribosomes. The location and the enormously high content of negatively charged amino acids lead to the hypothesis that NO29 might be involved in the nuclear and nucleolar accumulation of ribosomal proteins and the coordinated assembly of pre-ribosomal particles.

SUBMITTER: Zirwes RF

PROVIDER: S-EPMC23475 | biostudies-literature | 1997 Oct

REPOSITORIES: biostudies-literature

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Identification of a small, very acidic constitutive nucleolar protein (NO29) as a member of the nucleoplasmin family.

Zirwes R F RF Schmidt-Zachmann M S MS Franke W W WW

Proceedings of the National Academy of Sciences of the United States of America 19971001 21

We report the discovery and molecular characterization of a small and very acidic nucleolar protein of an SDS/PAGE mobility corresponding to Mr 29,000 (NO29). The cDNA-deduced sequence of the Xenopus laevis protein defines a polypeptide of a calculated molecular mass of 20,121 and a pI of 3.75, with an extended acidic region near its C terminus, and is related to the major nucleolar protein, NO38, and the histone-binding protein, nucleoplasmin. This member of the nucleoplasmin family of proteins ...[more]

PMID: 9326619

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Project description:Trefoil factor family member 2 (Tff2) is significantly involved in intestinal tumor growth in ApcMin/+ mice, which can be used as a human colon cancer model. TFF2, which encodes TFF2 (spasmolytic protein 1) is highly expressed in human cancer tissues, including the pancreas, colon and bile ducts, as well as in normal gastric and duodenum tissues. By contrast, TFF2 exhibits low expression levels in other normal tissues, including the small and large intestine. Furthermore, TFF2 expression has not been detected in DLD-1 cells, a cell line derived from human colon cancer. The trigger of TFF2 expression in normal and tumor cells remains unknown. Highly malignant tumor tissues are characterized by higher temperatures and lower pH (6.2-6.9) than in normal tissues, where the normal pH ranges from 7.2 to 7.4. This microenvironment exacerbates malignancy by promoting the acquisition of cell death resistance, drug resistance and immune escape. Therefore, the present study examined how TFF2 expression is affected in cultured cells that imitate the tumor tissue microenvironment. The incubation temperature was increased from 37 to 40˚C, but no expression of TFF2 was induced. Subsequently, a culture solution with an acidic pH was prepared to simulate the Warburg effect in tumors. TFF2 expression was increased by 42.8- and 5.8-fold in cells cultured in acidic medium at pH 6.5 and 6.8 compared with at pH 7.4, respectively, as determined using the relative quantification method following quantitative polymerase chain reaction. The present study also analyzed fluctuations in the expression levels of genes other than TFF2, under acidic conditions. Acidic conditions upregulated the expression of genes related to cell membranes and glycoproteins, based on the Database for Annotation, Visualization, and Integrated Discovery. In conclusion, TFF2 was highly expressed under acidic conditions, implying that it may have an important function in protecting the plasma membrane from acidic environments in both normal and cancer cells. These findings warrant further investigation of TFF2 as a target of cancer therapy and diagnosis.

Project description:Trefoil factor family member 2 (Tff2) is significantly involved in intestinal tumor growth in ApcMin/+ mice, which can be used as a human colon cancer model. TFF2, which encodes TFF2 (spasmolytic protein 1) is highly expressed in human cancer tissues, including the pancreas, colon and bile ducts, as well as in normal gastric and duodenum tissues. By contrast, TFF2 exhibits low expression levels in other normal tissues, including the small and large intestine. Furthermore, TFF2 expression has not been detected in DLD-1 cells, a cell line derived from human colon cancer. What induces TFF2 expression in normal and tumor cells is still unknown. Highly malignant tumor tissues are characterized by higher temperatures and lower pH (6.2-6.9) than in normal tissues, where normal pH ranges from 7.2 to 7.4. This microenvironment exacerbates malignancy by promoting the acquisition of cell death resistance, drug resistance and immune escape. Therefore, the present study examined how TFF2 expression is affected in cultured cells that imitate the tumor tissue microenvironment. The incubation temperature was increased from 37 to 40°C, but no expression of TFF2 was induced. Subsequently, a culture solution with an acidic pH was prepared to simulate the Warburg effect in tumors. TFF2 expression was increased by 42.8- and 5.8-fold in cells cultured in acidic medium at pH 6.5 and 6.8 compared with at pH 7.4, respectively, as determined using the relative quantification method following quantitative polymerase chain reaction. The present study also analyzed fluctuations in the expression levels of genes other than TFF2, under acidic conditions. Acidic conditions upregulated the expression of genes related to cell membranes and glycoproteins, based on the Database for Annotation, Visualization, and Integrated Discovery. In conclusion, TFF2 was highly expressed under acidic conditions, implying that it may have an important function in protecting the plasma membrane from acidic environments in both normal and cancer cells. These findings warrant further investigation of TFF2 as a target of cancer therapy and diagnosis.

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Dataset Information

Identification of a small, very acidic constitutive nucleolar protein (NO29) as a member of the nucleoplasmin family.

Publications

Identification of a small, very acidic constitutive nucleolar protein (NO29) as a member of the nucleoplasmin family.

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