A novel tomato MYC-type ICE1-like transcription factor, SlICE1a, confers cold, osmotic and salt tolerance in transgenic tobacco.

ICE1 (inducer of CBF expression 1), a MYC-type bHLH transcription factor, is an important activator of CBF3/DREB1A for regulating cold signaling and stress tolerance. In this study, we isolated the novel ICE1-like gene SlICE1a from tomato which contains the conserved bHLH domain, an S-rich motif, and ACT-domain. It is localized in the nucleus and harbors transcription-activating activity in the N-terminal. In addition, the SlICE1a transcript is slightly upregulated by cold stress, salt stress, and osmotic stress. SlICE1a overexpression in tobacco enhances the induction of CBF/DREB and their target genes, consequently increasing the levels of proline, soluble sugars, and late embryogenesis abundant (LEA) proteins, and enhancing tolerance to cold stress, osmotic stress, and salt stress. SlICE1a functions in abiotic stress responses by regulating the expression of stress-tolerant genes, and is thus beneficial for crop improvement.

Overexpression of tomato enhancer of SOS3-1 (LeENH1) in tobacco enhanced salinity tolerance by excluding Na+ from the cytosol.

The salt overly sensitive pathway has an important function in plant salinity tolerance. The enhancer of SOS3-1 (ENH1) participates in a new salinity stress pathway with SOS2 but without SOS3. To investigate the physiological effects and functional mechanism of ENH1 under salt stress, ENH1 was isolated from tomato and overexpressed in tobacco. Under salt stress, the sprouting percentage, fresh weight, and dry weight of transgenic plants were higher than those of wild-type (WT) plants. Under salt stress, the chlorophyll content, net photosynthetic rate, and maximal photochemical efficiency of PSII in transgenic plants decreased more slowly than those in WT plants. The overexpression of LeENH1 in tobacco excluded Na(+) from the cytosol and retained high K(+) levels in the cytosol to reestablish ion homeostasis. Higher thylakoid-bound ascorbate peroxidase activity and lower reactive oxygen species levels were found in transgenic plants under salt stress.

[Clinical studies of dynamic changes on the renal injury indicators of acute paraquat poisoning].

OBJECTIVE: To investigate the clinical significance of dynamic changes of blood urea nitrogen (BUN), serum creatinine (Cr), serum cystatin (Cys C) and urinary protein on renal injury with paraquat poisoning. METHODS: According to the clinical manifestation and curative effect, the clinical information was analyzed retrospectively in 35 cases of acute paraquat poisoning, survival after eight weeks as the standard. Poisoning patients were taken a fasting blood 5 ml and the middle of urinary on the 1st day, 3rd day, 7th day, 14th day, 21st day and 8 weeks after the poisoning. Then the levels of serum BUN, Cr, Cys C and urinary protein were detected by automatic biochemistry analyzer. 30 cases healthy subjects were randomly selected as normal control group, and discharged kidney disease and other diseases of urinary system history. The same laboratory subjects have been done. RESULTS: The level of serum Bun, Cr, Cys C of survival group increased significantly compared with control group within 21 days (P < 0.05). The level of serum BUN, Cr Cys C decreased on the 14th day. The decreased level of serum Cys C was lower than that of serum BUN and Cr. The renal function of 29 cases among 35 cases survival patients recovered on 21st day. The renal function of 31 cases among 35 cases survival patients recovered 8 weeks late. The positive rate of urinary protein of survival patients was high in the early intoxication (76.9%). CONCLUSION: Serum Cys C is sensitive indicator to reveal the kidney injury on paraquat poisoning patients and have higher value of clinical applications in the diagnosis of the kidney injury of paraquat poisoning, which sensitivity is higher than serum BUN and Cr. The kidney injury caused by paraquat poisoning is reversible.

[Function of a novel brain-specific gene LRRC4].

OBJECTIVE: To study the suppressive effect of LRRC4 gene on human glioma U251 cells and further investigate its biological functions. METHODS: H&E, DNA and AgNORs stainings were performed on LRRC4-transfected U251 cells, mock-transfected U251 cells and non-transfected U251 cells, respectively. Quantitative analysis including cell morphometry, DNA content, DNA ploidy, silver stained argyrophilic nucleolar organizer regions (AgNORs) were investigated by image analysis. Flow cytometry was employed to determine the difference of cell cycle distribution and MTT staining was used to elucidate the activity of the LRRC4-transfected U251 cells. RESULTS: The morphological cell parameters such as area, perimeter and diameter, DNA content, chromosomal aneupoloidy, mean area of AgNORs particles and mean nucleus area of the LRRC4-transfected U251 cells were remarkably decreased compared to those of the mock-transfected and non-transfected U251 cells (P < 0.05, P < 0.01). Meanwhile, significant accumulation of cells in G(0)/G(1) phase but decrease of cells in S and G(2)/M phase, was observed in transfected U251 cells compared to those of the mock-transfected and non-transfected U251 cells (P < 0.05, P < 0.01). MTT staining showed that proliferation activity of both the mock- and non-trasfected U251 cells was significantly higher than that of the U251 cells transfected with LRRC4 gene (P < 0.01). CONCLUSION: LRRC4 gene might be involved in tumor suppression by restraining DNA synthesis and the nucleoli organizer regions-associated proteins, keeping the cell cycles in phase G(0)/G(1) and reducing proliferation activity of the glioma cells. Morphometry combined with other techniques such as flow cytometry and MTT staining can well elucidate the biological function of novel genes.

Study of a novel brain relatively specific gene LRRC4 involved in glioma tumorigenesis suppression using the Tet-on system.

LRRC4 is a novel relatively specific gene, which displays significant down-regulation in primary brain tumor biopsies and has the potential to suppress brain tumor growth. In this study, we investigated the growth inhibitory effect of LRRC4 on tumorigencity in vivo and on cell proliferation in vitro by a tetracycline-inducible expression system. Results showed that LRRC4 significantly reduced the growth and malignant grade of xenografts arising from glioblastoma U251MG cells. Cell proliferation was markedly inhibited after U251MG Tet-on-LRRC4 cell induction with doxycycline. Flow cytometry and Western blot analysis demonstrated that LRRC4 mediated a delay of the cell cycle in late G1, possibly through up-regulating the expressions of p21Waf1/cip1 and p27Kip1 and down-regulating the expressions of cyclin-dependent kinase 2, retinoblastoma protein and epidermal growth factor receptors. Together, these findings provide clues to the function of LRRC4 as a negative regulator of cell growth and underscore a link between the above-mentioned cyclins, cyclin-associated molecules and tumorigenicity.

Expression of tumor related gene NAG6 in gastric cancer and restriction fragment length polymorphism analysis.

AIM: NAG6 gene is a novel tumor related gene identified recently. This study was designed to examine the expression of this gene in gastric cancer and corresponding normal tissues, and to investigate its role in the occurrence and development of gastric cancer, also to study if the genetic structure of NAG6 was altered in gastric cancer. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR), Northern blot analysis and dot hybridization were used to compare the expression level of NAG6 gene in 42 cases of gastric cancer tissues with their corresponding normal tissues of the same patients respectively. In addition, restriction fragment length polymorphism (RFLP) analysis was adopted to study if the genetic structure of NAG6 was altered in gastric carcinomas. RESULTS: The expression of NAG6 in 57.1% gastric cancer tissues (25/42) was absent by RT-PCR analysis. The down-regulation rate of NAG6 in gastric cancer tissues was significantly higher than that in corresponding normal tissues (P<0.01). However no correlation between the down-regulation of NAG6 and lymph-node and/or distance metastasis was found in this study (P>0.05). Dot hybridization confirmed the results of RT-PCR. Furthermore, the results of EcoRI RFLP analysis of NAG6 gene demonstrated that 3 of 7 cases of gastric cancer showed loss of 5 kb fragment in comparison with their corresponding normal tissues. CONCLUSION: NAG6 gene is significantly down regulated in gastric cancer. The loss of genetic materials may be the cause of down-regulation of NAG6 expression. This seems to suggest that NAG6 may represent a candidate of putative tumor suppressor gene at 7q31-32 loci associated with gastric carcinoma. The down-regulation of this gene may play a role in occurrence and development of this disease, however it may not be associated with lymph node and/or distance metastasis.

A susceptibility locus at chromosome 3p21 linked to familial nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) poses one of the serious health problems in southern Chinese, with an incidence rate ranging from 15 to 50/100,000. Chromosome translocation t(1;3) and frequent loss of heterogeneity on short arms of chromosome 3 and 9 have been reported to be associated with NPC, and a genome-wide scan identified an NPC susceptibility locus on chromosome 4p15.1-q12 recently. In our study, we collected samples from 18 families at high risk of NPC from the Hunan province in southern China, genotyped with a panel of polymorphic markers on short arms of chromosomes 3, 9, and 4p15.1-q12. A locus on 3p21 was identified to link to NPC with a maximum logarithm of odds for linkage score of 4.18. Fine mapping located the locus to a 13.6-cM region on 3p21.31-21.2, where a tumor suppressor gene cluster resided. Our findings identified a novel locus for NPC and provided a map location for susceptibility genes candidates. In contrast to a recent study, no significant evidence for NPC linkage to chromosomes 4 and 9 was observed.

Expression of LRRC4 has the potential to decrease the growth rate and tumorigenesis of glioblastoma cell line U251.

BACKGROUND & OBJECTIVE: LRRC4 is a novel gene that the author has identified recently, which displayed significant downregulation in primary brain tumor biopsies. This study was designed to investigate if LRRC4 has the potential of suppressing brain tumor growth. METHODS: The full-length coding region of LRRC4 gene was subcloned into the expression vector pcDNA3.1, the recombinant was introduced into the glioblastoma cell line U251 by liposome transfection, and the U251 cells stably expressing LRRC4 gene were established by G418 selection. Furthermore, cell proliferation assay, soft agar assay, tumorigenesis assay were taken to examine the effect of LRRC4 expression on cell growth and tumor formation. RESULTS: U251 cells stably expressing full-length coding region of LRRC4 were established by lipofection-mediated transfection and selected for further study. Compared with the nontransfected and vector-transfected cells, the cells transfected with LRRC4 cDNA exhibited a significant increase of expression of LRRC4 mRNA by Northern blot analysis. Further, when cell proliferation was followed over several days, the cells expressing the transfected LRRC4 cDNA grew more slowly than nontransfected cells. Consistently, the cells transfected with LRRC4 exhibited markedly lower colony formation rate. These clones were injected into athymic nude mice who was killed after 40 days and the tumor sizes were evaluated. Tumor volume in mice was significantly smaller in the group of cells stably transfected with LRRC4 cDNA than in the control. CONCLUSION: LRRC4 gene may be transfected into the human glioblastoma cell line U251. The expression of LRRC4 in U251 cells may have the potential to suppress tumor cell growth and the tumorigenesis of U251 cell transplanted in nude mice.

Expression of tumor related genes NGX6, NAG-7, BRD7 in gastric and colorectal cancer.

AIM: NGX6, NAG-7 and BRD7 genes are tumor related genes, which have been newly cloned by positional candidate cloning strategy. This study was designed to investigate the expression levels of NGX6, NAG-7 and BRD7 genes in human gastric and colorectal cancer tissues, and their corresponding normal tissues, and to investigate whether these genes play a role in the pathogenesis of gastric and colorectal cancers. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR), dot hybridization and Northern blot analysis were used to compare the expression levels of NGX6, NAG-7 and BRD7 genes in 34 gastric cancer tissues and 34 colorectal cancer tissues with their corresponding normal tissues of the same patients, respectively. RESULTS: Among the 34 colorectal cancer specimens and the 34 gastric cancer specimens, the expression of NGX6 in 25 colorectal cancer tissues was absent or very weak (73.5 %) by RT-PCR analysis. The down-regulation rate of NGX6 in colorectal cancer tissues was significantly higher than that in corresponding normal tissues (26.5 %,9/34) (P<0.005). Moreover, the down-regulation of NGX6 was significantly correlated with lymph node and/or distance metastases. Patients with lymph node and/or distance metastasis had much higher down-regulation rate of NGX6 than patients without metastases (93.8 % vs 55.6 %, P<0.05). However no correlation was found between the expression of NGX6 and pathologic type of colorectal cancer in this study, and also the expression of NGX6 did not display any difference between gastric cancer and corresponding normal tissues (58.8 % vs 70.6 %, P>0.25). Dot hybridization and Northern blot analysis confirmed the results of RT-PCR. Furthermore, NAG-7 and BRD7 mRNA was not up- or down-regulated in gastric and colorectal cancers compared with their corresponding normal tissues in our study. CONCLUSION: The down-regulation of NGX6 may be closely associated with tumorigenesis and metastasis of colorectal carcinoma. However, it may not contribute to the development and progression of gastric carcinoma. In addition, the expression levels of NAG-7, and BRD7 did not alter in gastric and colorectal cancers. This seems to suggest that NAG-7 and BRD7 genes may not play a role in gastric and colorectal carcinogenesis.

[In situ expression of connexins in various carcinomas].

BACKGROUND & OBJECTIVE: Malignant cells are often associated with aberrant expression or localization of connexins. Expression of Cx26, Cx32, Cx43, and Cx45 genes were studied to gain their expression profile in tissue microarrayers consisting of various carcinomas and to elucidate their function in carcinogenesis. METHODS: Basing on the principle of constructing tissue microarrays, the authors take use of self-made tissue arrayer to construct tissue microarrays for the different kinds of cancer specimens. Meanwhile, expression of connexin(Cx) genes, such as Cx32, Cx26, Cx43, and Cx45 in the tissue microarrays were detected in 292 cases of tumor tissues and 89 paratumor tissues by immunohistochemistry. RESULTS: (1) Three kinds of tissue microarrays consisting samples from 20 different carcinomas were constructed successfully, which contained 360, 200, or 100 spots in each receptive paraffin block with tissue cylinder of 0.75mm or 0.6mm diameter respectively.(2) The expression profiles of Cx32, Cx26, Cx43, and Cx45 in 20 kinds of carcinomas and their related adjacent-cancer tissues were gained, which were widely low expressed in carcinomas especially in nasopharyngeal carcinomas. Expression of Cx26, Cx32, Cx43, and Cx45 in carcinomas such as carcinomas of colon and recta, hepatocellular carcinomas, gastric carcinomas, lung carcinomas and thyroid cancers were significantly lower than their related adjacent-cancer tissues. CONCLUSION: Low expression of Cx26, Cx32, Cx43, and Cx45 might play crucial roles in carcinogenesis of many kinds of carcinomas. Tissue microarrays consisting of many different kinds of carcinomas provide a new high-throughout tool for rapid and comprehensive molecular expression profiles of carcinomas, such as connexin genes.

[Identification of digital differential expression patterns of a novel human gene (UBAP1) by an expressed sequence tag strategy].

BACKGROUND & OBJECTIVES: This study was designed to identify differential expression patterns in tumor and normal tissues of the human novel gene, UBAP1, a putative nasopharyngeal carcinoma (NPC) relate gene, which is located at human chromosome 9p21-22 where loss of heterozygosity frequently occurs in NPC. METHODS: Based on the generation of expressed sequence tags (ESTs), in the authors' electronic Northern blot, complete cDNA of ubap1 gene was taken as a "probe" sequence, and human EST Database search of GenBank was carried out using BLASTn programs. A report generated in a BLAST search of ubap1 gene sequence against an EST database consisting of such 'pedigree' ESTs allows the inference of the gene's tissue distribution. Furthermore, differential RT-PCR was used to describe the expression patterns of ubap1 in partial tumor tissues. RESULTS: Database surveys indicated ubap1 gene was not only ubiquitously expressed in many normal tissues with various levels but also differentially expressed in different tumor tissues, especially down-regulated in multiple neoplastic tissues such as brain, breast, skin, colon, testis, and uterus tumor tissues. Furthermore, differential RT-PCR analysis demonstrated expression of ubap1 was down-regulated or absent in 7 of 11(64%) meningioma samples and 13 of 18 (72%) colorectal tumor tissues respectively. CONCLUSIONS: The authors present an EST approach that proved to be useful for the identification of differential expression patterns of ubap1 in different tumors. These findings could be valuable for the investigation of the mechanism of UBAP1 gene exhibiting differential expression, potentially involved in the progression of multiple cancers.

Preliminary Function Study of NAG7 Using Two-dimensional Electrophoresis and Mass Spectrometry.

In search of mechanisms of function of NAG7 gene, a powerful new tool for the unambiguous characterization of gel-separated proteins is accomplished by the combination of mass spectrometry and sequence database searching. NAG7, a novel putative tumor suppressor gene, located on 3p25.3, was introduced into HNE1 cells by liposome transfection. We used two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) to identify proteins that were overexpressed in NAG7 transfected cells. After staining and image analysis, spots of interest were isolated and subjected to mass spectrometry (MS). We found nine proteins, which up-regulated in NAG7 transfected cells and be identified by MS. These proteins included growth arrest specific protein, DNA binding protein, c-myc promoter-binding protein and caspase 6 etc., which involved in cell cycling, transcription regulation, and apoptosis. NAG7 may exert the function by up-regulating the expression of these proteins.

Cloning and Expression Analysis of a Novel Gene, UBAP1, Possibly Involved in Ubiquitin Pathway.

The 9p21-22 region shows loss of heterozygosity in up to 60% of human nasopharyngeal carcinomas (NPC), indicating the presence of a tumor suppressor gene in this region. We have identified a novel minimal common deletion region at 9p21-22. Twenty-two epithelial-derived expressed sequence tags (ESTs) in this critical region were systematically screened by differential RT-PCR to investigate the expression patterns in NPC cell line HNE1 and primary cultures of normal nasopharyngeal epithelial cells. One of these ESTs was found down-expressed in HNE1, whose differential expression was confirmed by Northern blot. Subsequently the corresponding gene sequence for this EST was established by cDNA cloning and RACE procedures (GenBank Accession No.AF222043). Furthermore, a mouse homologueof this gene was identified (GenBank Accession No.AF275549). This gene is 2.7 kb long and contains two UBA domains. It is a new member of UBA domain protein family, encoding a putative protein of 502 amino acids with a theoretical molecular mass of 55 kD, so we have named this gene UBAP1 for ubiquitin associated protein 1 (HUGO Gene Nomenclature Committee-approved symbol). Northern blot and RT-PCR analysis demonstrated a ubiquitous pattern of gene expression in human and mouse tissues. Direct sequencing analysis of the coding region of hUBAP1 following RT-PCR failed to reveal any mutations in a preliminary screening of NPC cell line HNE1 and primary nasopharyngeal carcinomas samples. However, more detailed analysis is to be performed to reveal if fine mutations of this gene are present in NPC.