Wyniki wyszukiwania - Biblioteka Nauki

1

Increased expression of ribosomal protein S2 in liver tumors, posthepactomized livers, and proliferating hepatocytes in vitro.

100%

Kowalczyk P. , Woszczyński M. , Ostrowski J.

Acta Biochimica Polonica

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2002

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tom 49

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nr 3

615-624

EN

The ribosomal protein S2 (RPS2) is encoded by a gene from the highly conserved mammalian repetitive gene family LLRep3. It participates in aminoacyl-transfer RNA binding to ribosome, potentially affecting the fidelity of mRNA translation. These studies were designed to measure the expression of RPS2 during increased cell proliferation. Using Western and Northern blot analyses, we found that the levels of RPS2 protein and its corresponding mRNA were higher in mouse hepatocellular carcinoma, in mouse livers after one-third partial hepatectomy, and in serum-starved cultured hepatocytes following serum treatment. Our study shows that the increased expression of RPS2 correlates with increased cell proliferation. However, whether the altered expression of this protein reflects its involvement in cellular proliferation or represents an associated phenomena is still a key question that needs to be explored.

2

Expression of genes encoding mitochondrial proteins can distinguish nonalcoholic steatosis from steatohepatitis

100%

Bragoszewski P. , Habior A. , Walewska-Zielecka B. , Ostrowski J.

Acta Biochimica Polonica

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2007

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tom 54

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nr 2

341-348

EN

In patients without substantial alcohol use, triglyceride accumulation in the liver can lead to nonalcoholic fatty liver disease (NAFLD) that may progress to nonalcoholic steatohepatitis (NASH). The differential diagnosis between NAFLD and NASH can be accomplished only by morphological examination. Although the relationship between mitochondrial dysfunction and the progression of liver pathologic changes has been described, the exact mechanisms initiating primary liver steatosis and its progression to NASH are unknown. We selected 16 genes encoding mitochondrial proteins which expression was compared by quantitative RT-PCR in liver tissue samples taken from patients with NAFLD and NASH. We found that 6 of the 16 examined genes were differentially expressed in NAFLD versus NASH patients. The expression of hepatic HK1, UCP2, ME2, and ME3 appeared to be higher in NASH than in NAFLD patients, whereas HMGCS2 and hnRNPK expression was lower in NASH patients. Although the severity of liver morphological injury in the spectrum of NAFLD-NASH may be defined at the molecular level, expression of these selected 6 genes cannot be used as a molecular marker aiding histological examination. Moreover, it is still unclear whether these differences in hepatic gene expression profiles truly reflect the progression of morphological abnormalities or rather indicate various metabolic and hormonal states in patients with different degrees of fatty liver disease.

3

A common cis-element in promoters of protein synthesis and cell cycle genes

88%

Wyrwicz L. S. , Gaj P. , Hoffmann M. , Rychlewski L. , Ostrowski J.

Acta Biochimica Polonica

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2007

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tom 54

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nr 1

89-98

EN

Gene promoters contain several classes of functional sequence elements (cis elements) recognized by protein agents, e.g. transcription factors and essential components of the transcription machinery. Here we describe a common DNA regulatory element (tandem TCTCGCGAGA motif) of human TATA-less promoters. A combination of bioinformatic and experimental methodology suggests that the element can be critical for expression of genes involved in enhanced protein synthesis and the G1/S transition in the cell cycle. The motif was identified in a substantial fraction of promoters of cell cycle genes, like cyclins (CCNC, CCNG1), as well as transcription regulators (TAF7, TAF13, KLF7, NCOA2), chromatin structure modulators (HDAC2, TAF6L), translation initiation factors (EIF5, EIF2S1, EIF4G2, EIF3S8, EIF4) and previously reported 18 ribosomal protein genes. Since the motif can define a subset of promoters with a distinct mechanism of activation involved in regulation of expression of about 5% of human genes, further investigation of this regulatory element is an emerging task.

4

Mitochondria-associated satellite I RNA binds to hnRNP K protein

75%

Klimek-Tomczak K. , Mikula M. , Dzwonek A. , Paziewska A. , Wyrwicz L. S. , Hennig E. E. , Ostrowski J.

Acta Biochimica Polonica

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2006

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tom 53

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nr 1

169-178

EN

hnRNP K protein, which localizes to the nucleus, cytoplasm and mitochondria, is involved in the various cellular processes that compose gene expression. We used a SAGE-based assay to profile RNAs associated with hnRNP K protein in rat mitochondria. RNA was isolated from mitoplasts obtained from highly purified and RNase-treated mitochondria. Total RNA and RNA associated with hnRNP K protein were then used as input material for generating two SAGE libraries. Mitochondrion-derived tags isolated from the total mitoplast RNA library represented 86.3%, while those isolated from the library constructed from RNA associated with hnRNP K protein represented only 28.2% of selected tags. Thus, an unexpected number of nuclear-encoded RNAs were purified from mitochondria. Many of these transcripts were co-purified with hnRNP K protein, and high levels of nuclear-encoded RNAs co-immunoprecipitating with K protein corresponded to elevated hnRNP K protein levels of the organelle. The most abundant RNAs that were co-purified with hnRNP K protein represented transcripts originating from satellite I DNA. While satellite I RNA levels were higher in the nucleus and cytoplasm than in mitochondria, the most abundant binding of satellite I transcripts to hnRNP K protein was found in mitochondria. The role of satellite I RNA in mitochondria remains to be elucidated.

5

Evaluation of rainfall-runoff models performance for flood computation in mountainous basins

75%

Soczyńska U. , Nowicka B. , Somorowska U. , Ignar S. , Górski D. , Ostrowski J.

Miscellanea Geographica. Regional Studies on Development

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1996

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tom 7

97-106

6

Up-regulation of human PNPase mRNA by β-interferon has no effect on protein level in melanoma cell lines

63%

Gewartowski K. , Tomecki R. , Muchowski L. , Aleksandra Dmochowska , Dzwonek A. , Malecki M. , Skurzak H. , Ostrowski J. , Stepien P. P.

Acta Biochimica Polonica

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2006

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tom 53

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nr 1

179-188

EN

Human mitochondrial polynucleotide phosphorylase (hPNPase) is an exoribonuclease localized in mitochondria. The exact physiological function of this enzyme is unknown. Recent studies have revealed the existence of a relationship between induction of hPNPase mRNA and both cellular senescence and growth arrest of melanoma cells following β-interferon treatment. The aim of this study was to verify whether the augmented hPNPase mRNA level results in increase of the protein level. In several cell lines established from five metastatic melanoma patients we did not find any such correlation. However, an elevated level of hPNPase protein was observed in interferon-induced HeLa and Jurkat cells. This increase was correlated with a slight shortening of poly(A) tails of mitochondrial ND3 transcript.

7

Gene expression alterations induced by low molecular weight heparin during bowel anastomosis healing in rats

51%

Krześniak N. , Paziewska A. , Rubel T. , Skrzypczak M. , Mikula M. , Dzwonek A. , Goryca K. , Wyrwicz L. S. , Jarosz D. , Laubitz D. , Woszczyński M. , Bielecki K. , Ostrowski J.

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nr 1

79-87

EN

Colon anastomosis is therapeutically challenging because multiple, usually undetectable factors influence a spectrum of repair mechanisms. We hypothesized that low molecular weight heparins, routinely administered perioperatively, may differentially affect gene expression related to colon healing. Twenty pairs of untreated and enoxaparin-treated rats underwent left-side hemicolectomy with a primary end-to-end anastomosis. Normal colon and anastomotic bowel segments were resected on day 0 and on days 1, 3, 5, and 7 after surgery, respectively. Serial anastomosis transverse cross-sections were evaluated microscopically and by microarray (Rat Genome 230 2.0, Affymetrix). Differentially expressed probe sets were annotated with Gene Ontology. We also examined the influence of enoxaparin on fibroblast proliferation and viability in vitro. Among the 5476 probe sets, we identified differential expression at each healing time point, yielding 79 subcategories. Most indicated genes were involved in wound healing, including multicellular organismal development, locomotory behavior, immune response, cell adhesion, inflammatory response, cell-cell signaling, blood vessel development, and tissue remodeling. Although we found no intensity differences in histological features of healing between enoxaparin-treated and control rats, treatment did induce significant expression changes during early healing. Of these changes, 83 probe sets exhibited at least twofold changes and represented different functional annotations, including inflammatory response, regulation of transcription, regulation of apoptosis, and angiogenesis. Fibroblast culture confirmed an anti-viability effect of enoxaparin. Enoxaparin affects colon wound-related gene expression profiles, but further studies will resolve whether heparin treatment is a risk factor after intestinal surgery, at least in some patients.