Egr1 deficiency disrupts dynamic equilibrium of chondrocyte extracellular matrix through PPARγ/RUNX2 signaling pathways.

BACKGROUND: This study is to investigate the effect of Egr1 on the mineralization and accumulation of chondrocyte extracellular matrix. METHODS: The femoral heads of patients of various heights were collected. Egr1 knockout mice were used. Their limb lengtha nd body weight were assessed. The bone characteristics were detected by micro-CT scan and histological staining. Immature murine articular chondrocytes (iMACs) were isolated. Gross morphology was observed by histological staining. Relevant mRNA and protein expression were detected by qRT-PCR and Western blot, respectively. the related proteins were observed by immunohistochemical staining and immunofluorescence assay. Chromatin immunoprecipitation and reporter gene assay were also used. TUNEL was used to detect apoptosis. RESULTS: It was found that shorter patients had reduced Egr1 expression levels in the hypertrophic cartilage zone of the femoral head. In addition, Egr1 knockout mice exhibited reduced body size. Micro-CT analysis showed that these mice also had reduced bone volume. Safranin-O staining showed that the extracellular matrix of these mice exhibited a relatively limited degree of mineralization, and TUNEL staining showed reduced cell apoptosis levels. After transfecting the iMACs with dominant-negative Egr1 adenoviruses to inhibit Egr1, the enzymes of Adamst4, Adamst5, Mmp3 and Mmp13 were significantly upregulated. ChIP and luciferase assays revealed that Egr1 might regulate the chondrocyte extracellular matrix by the PPARγ/RUNX2 signaling pathways. CONCLUSION: Egr1 has an important regulatory effect on the dynamic equilibrium of the chondrocyte extracellular matrix, which may be achieved through the PPARγ/RUNX2 signaling pathways.

Interface energy effect on the dispersion relation of nano-sized cylindrical piezoelectric/piezomagnetic composites.

Interface between the constituents plays an important role in the non-destructive detection of smart piezoelectric/piezomagnetic devices. The propagation of SH waves in nano-sized cylindrically multiferroic composites consisting of a piezoelectric layer and a piezomagnetic central cylinder is investigated, and the size-dependent dispersion relation with interface effect is derived. The general solutions of decoupled governing equation in different regions are expressed by using Bessel functions, and the unknown coefficients are determined by satisfying the boundary conditions at the inner interface with negligible thickness and the outer surface of the structure. Through the numerical examples of dispersion relation, it is found that the interface around the nano-cylinder may remarkably reduce the phase velocity, depending on the combination of the value of thickness ratio and the surface condition. The interface shows different effect on the first and second modes of dispersion relation.

[The expression level of FtsZ protein during the dedifferentiation and redifferentiation of explants of Nicotiana tobacum].

The explants cells of Nicotiana Tobacum undergo the process of dedifferentiation and redifferentiation under the treatment of phytohormone with different contentrations. By monitoring the change of plastids and the expression of FtsZ protein, which functions in the progress of chloroplast division, we show that chloroplasts turn into amyloid and hypostasis when explants dedifferent and at the same time the expression of FtsZ proteins decreases. When explants redifferent and bud, hypostasis turn back into the chloroplast and the expression of FtsZ protein restores. The concurrence of fluctuant expression of FtsZ protein and the progress of bud differentiation and formation of chloroplast play essential roles in the growth of green plant.

[Study of the metastasis-associated genes and its copy numbers variation in highly metastatic epithelial ovarian cancer].

OBJECTIVE: To investigate the relationship of the metastasis-associated genes and its copy numbers variation in the highly metastatic human epithelial ovarian cancer cell line HO-8910PM. METHODS: The differentially expressed genes and its copy number variation between HO-8910PM cell line and normal ovarian tissues was detected by human genome U133A 2.0 gene chip and human mapping 10K array 2.0 gene chip, and the data was analyzed by bioinformatics. Some of metastasis-associated genes were validated the results of single nucleotide polymorphism (SNP) and cDNA chips by fluorescence in situ hybridization (FISH) and real-time quantitative PCR. RESULTS: Integrate analysis of two gene chips data showed that there were 385 differentially expressed genes in the same and 379 SNP positional point (6 of them, included 2 genes) between HO-8910PM cell line and normal ovarian tissues, these copy number amplification of 379 SNP positional point of chromosome were > or = 3, which had 240, deletion < or = 1 had 139. Chromosome location analysis showed that there were 385 differentially expressed genes located at all chromosomes, and 261 of them (67.8%, 261/385) located at 10 chromosomes, included that 34 (8.8%), 33 (8.6%), 28 (7.3%), 27 (7.0%), 25 (6.5%), 24 (6.2%) of them located at chromosome 3, 2, 9, 10, 1 and 11 respectively, and 23 (6.0%) of them at chromosome 6 and 12 each, 22 (5.7%) of them at chromosome 4 and 5 each. For the function of differentially expressed genes, the results showed that 99 (25.7%) genes belonged to the family of enzymes and their regulators, 54 (14.0%) genes associated with signal transduction, 50 (13.0%) genes associated with nucleic acid binding, and 36 (9.4%) genes associated with protein binding. CONCLUSION: We have demonstrated that there are 4 kinds of differentially expressed genes related to metastasis of ovarian cancer, which belonged to the families enzyme and its regulator, nucleic acid binding, signal transduction and protein binding, and located at chromosome 1, 2, 3, 4, 5, 6, 9, 10, 11 and 12.

Binding Energy and Spin-Orbit Splitting of a Hydrogenic Donor Impurity in AlGaN/GaN Triangle-Shaped Potential Quantum Well.

In the framework of effective-mass envelope function theory, including the effect of Rashba spin-orbit coupling, the binding energy E(b) and spin-orbit split energy Г of the ground state of a hydrogenic donor impurity in AlGaN/GaN triangle-shaped potential heterointerface are calculated. We find that with the electric field of the heterojunction increasing, (1) the effective width of quantum well W̅ decreases and (2) the binding energy increases monotonously, and in the mean time, (3) the spin-orbit split energy Г decreases drastically. (4) The maximum of Г is 1.22 meV when the electric field of heterointerface is 1 MV/cm.

Erratum to: Binding Energy and Spin-Orbit Splitting of a Hydrogenic Donor Impurity in AlGaN/GaN Triangle-Shaped Potential Quantum Well.

[This corrects the article DOI: 10.1007/s11671-009-9398-3.].

The involvement of NtFtsZ2-1 gene in the regulation of chloroplast division and expansion in tobacco.

Chloroplasts are a vital group of organelles of plants, yet the molecular mechanisms associated with their division remain poorly understood. Recent studies have revealed that the FtsZ protein, known as a key component in prokaryotic cell division, is involved in chloroplast division process. The NtFtsZ2-1 gene was isolated from Nicotiana tabacum by RT-PCR, and the sense and antisense expression plasmids were used to examine the function of NtFtsZ2-1 gene in transgenic tobacco. Light and confocal observations revealed that the normal chloroplast division process was severely disrupted in transgenic plants with enhanced or reduced expression of NtFtsZ2-1 gene. These chloroplasts were abnormally larger in size and fewer in number compared with that of the wild-type tobacco. But the total chloroplast plan area per mesophyll cell was conserved in sense, antisense and wild type tobaccos. Analyses of electron micrographs and chlorophyll content of different transgenic plants showed that constitutively enhancing or inhibiting the expression of NtFtsZ2-1 gene had no direct influence on the ultrastructure and photosynthetic ability of chloroplasts. Basing on these results, we suggest that NtFtsZ2-1 gene is involved in chloroplast division and expansion; the fluctuation of NtFtsZ2-1 expression level would alter normal chloroplast number and size in plant cells. In addition, the similarities of ultrastructure and photosynthetic ability of chloroplasts among sense, antisense and wild type tobaccos implies that a special mechanism regulate the relationship between chloroplast number and size to maximize photosynthetic rate.

Cloning and functional characterization of PpDBF1 gene encoding a DRE-binding transcription factor from Physcomitrella patens.

The dehydration-responsive element binding (DREB) transcription factors play central roles in regulating expression of stress-inducible genes under abiotic stresses. In the present work, PpDBF1 (Physcomitrella patens DRE-binding Factor1) containing a conserved AP2/ERF domain was isolated from the moss P. patens. Sequence comparison and phylogenetic analysis revealed that PpDBF1 belongs to the A-5 group of DREB transcription factor subfamily. The transcriptional activation activity and DNA-binding specificity of PpDBF1 were verified by yeast one-hybrid and electrophoretic mobility shift assay experiments, and its nuclear localization was demonstrated by particle biolisitics. PpDBF1 transcripts were accumulated under various abiotic stresses and phytohormones treatments in P. patens, and transgenic tobacco plants over-expressing PpDBF1 gained higher tolerance to salt, drought and cold stresses. These results suggest that PpDBF1 may play a role in P. patens as a DREB transcription factor, implying that similar regulating systems are conserved in moss and higher plants.

[Screening of carcinogenesis associated genes in gastric carcinoma by gene chip].

OBJECTIVE: To screen the carcinogenesis associated genes in gastric carcinoma by gene chip. METHODS: U133A (Affymetrix Santa Clara, CA) gene chip was used to detect differentially expressed genes in tumor tissues, paratumor mucosa and normal mucosa. Bioinformatics was used to analyze the screened results. RESULTS: A total of 150 genes were detected with a difference of expression levels more than 3 times in paratumor mucosa compared with normal gastric mucosa, 130 of which were up-regulated and 20 down-regulated. According to the function classifications of the differentially expressed genes, the most common ones were enzyme and enzyme regulon activity associated genes(28, 18.7% ). The frequencies of nuclei acid binding activity associated genes,signal transduction associated genes and protein binding associated genes were 11.3%, 10%, and 8.7% respectively. Seventy-one differentially expressed genes were detected both in tumor tissues and paratumor mucosa compared with normal mucosa, 61 of which were up-regulated and 10 down-regulated. Among these 71 genes,e leven genes were localized on chromosome 19, 6 on chromosome 1, 2, 16, 17 respectively. No abnormal differentially expressed gene were detected on chromosome 5, 14, 22 and Y. CONCLUSIONS: These 71 genes differentially expressed both in tumor tissues and paratumor mucosa may be associated with carcinogenesis of gastric carcinoma. The four kinds of genes associated with enzyme and enzyme regulon activity, nuclei acid binding activity, signal transduction, and protein binding should be the main genes for the study of carcinogenesis in gastric carcinoma.

Identification of differentially expressed genes in the high and low metastatic human ovarian cancer cell lines and analyses of their chromosomal localizations and functions.

Oligonucleotide microarrays were used to study the differences of gene expressions in high (H) and low (L) metastatic ovarian cancer cell lines and in normal ovarian tissues (C). Bioinformatics was used to identify novel genes and their functions as well as chromosomal localizations. A total of 409 genes were differentially expressed between the high and low metastatic ovarian cancer cell lines. Of them, 271 genes were up regulated (Signal Log Ratio[SLR] > or = 1), and 138 genes were down regulated (SLR < or = -1). Except one gene whose location was unknown, all these genes were localized randomly on all the chromosomes, with a majority of them localized to Chromosomes 1, 6, 2, 17, 3, 5 and 11. Chromosome 1 contained, 43 of them (10.7%), the most for a single chromosome. A total of 264 genes (64.7%) were localized on the short arm of the chromosome (q). Functional classification showed that the 104 (25.4%) genes coding for enzymes and enzyme regulators made up the largest functional group, followed by signal transduction activity genes (43, 10.5%), nucleic acid binding activity genes (42, 10.3%), and proteins binding activity genes (34, 8.3%). These four groups accounted for 54.5% of all the differentially expressed genes. In addition, the functions of 76 genes (18.6%) were unknown. Tumor metastasis is the result of a number of genes acting in concert. The four functional groups of genes classified among these genes and their abnormalities would be the focus of further studies on ovarian cancer metastasis.

[Blue light signaling in mosses].

Arabidopsis thaliana contains five identified blue light photoreceptors and at least one unidentified blue/UV-A light photoreceptor. Cryptochromes (CRY1 and CRY2) modulate photomorphological processes, flowering time, and circadian timing while phototrophins (PHOT1 and PHOT2) modulate phototropism, chloroplast movement, and stomatal opening. Flavins are the chromophores and absorb in the blue and UV-A range. Considerable information is known about the structure and mode of action of these photoreceptors. The moss Physcomitrella patens contains two identified cryptochromes (CRY1a and CRY1b) which modulate side branch formation and auxin metabolism. Blue light-induced chloroplast movement was mediated by four phototropins. Transduction of the blue/UV-A stimulus does involve calcium signaling in moss cells.

Function and chromosome location of differentially expressed genes in gastric cancer.

Using Affymetrix U133A oligonucleotide microarrays, screening was done for genes that were differentially expressed in gastric cancer (T) and normal gastric mucosa (C), and their chromosome location was characterized by bioinformatics. A total of 270 genes were found to have a difference in expression levels of more than eight times. Of them 157 were up-regulated (Signal Log Ratio [SLR] > or = 3), and 113 were down-regulated (SLR< or = -3). Except for, four genes with unknown localization, a vast majority of the genes were sporadically distributed over every chromosome. However, chromosome 1 contained the most differentially expressed genes (26 genes, or 9.8%), followed by chromosomes 11 and 19 (both 24 genes, or 9.1%). These genes were also more likely to be on the short-arm of the chromosome (q), which had 173 (65%). When these genes were classified according to their functions, it was found that most (67 genes, 24.8%) belonged to the enzymes and their regulators groups. The next group was the signal transduction genes group (43 genes, 15.9%). The rest of the top three groups were nucleic acid binding genes (17, 6.3%), transporter genes (15, 5.5%), and protein binding genes (12, 4.4%). These made up 56.9% of all the differentially expressed genes. There were also 50 genes of unknown function (18.5%). Therefore it was concluded that differentially expressed genes in gastric cancer seemed to be sporadically distributed across the genome, but most were found on chromosomes 1, 11 and 19. The five groups associated genes abnormality were important genes for further study on gastric cancer.

[Study on gene expression profile difference in gastric cancer, pericancerous mucosa and normal gastric mucosa from the distant cutting margin by oligonucleotide microarray].

OBJECTIVE: To study the difference of gene expression profiles in gastric cancer (T), pericancerous mucosa (P) and the gastric mucosa from distant cutting margin (C), and to screen an associated novel gene in early gastric carcinogenesis by oligonucleotide microarray. METHODS: U133A (Affymetrix, Santa Clara, CA) gene chip was used to detect the gene expression profile difference in T, P and C, respectively. Bioinformatics was used to analyze the detected results. RESULTS: When gastric cancer was compared with normal gastric mucosa, 766 genes were found,with a difference of more than four times in expression levels, including 530 up-regulated [Signal Log Ratio (SLR) > 2], and 236 down-regulated (SLR< -2). When P was compared with C, 64 genes were found, with a difference of more than four times in expression levels, including 50 up-regulated (SLR > 2), and 14 down-regulated (SLR< -2). Compared with C, a total of 143 genes with a difference of more than four times in expression levels both in T and P tissues. Of the 143 genes, 108 were up-regulated (SLR > 2), and 35 were down-regulated (SLR< -2). CONCLUSIONS: Gene chip can reveal 143 same genes both in pericancerous mucosa and gastric mucosa. These genes may be related to the carcinogenesis and development of early gastric cancer.

Gene expression profile differences in gastric cancer, pericancerous epithelium and normal gastric mucosa by gene chip.

AIM: To study the difference of gene expression in gastric cancer (T), pericancerous epithelium (P) and normal tissue of gastric mucosa (C), and to screen an associated novel gene in early gastric carcinogenesis by oligonucleotide microarray. METHODS: U133A (Affymetrix, Santa Clara, CA) gene chip was used to detect the gene expression profile difference in T, P and C, respectively. Bioinformatics was used to analyze the detected results. RESULTS: When gastric cancer was compared with normal gastric mucosa, 766 genes were found, with a difference of more than four times in expression levels. Of the 766 genes, 530 were up-regulated (Signal Log Ratio (SLR) >2), and 236 were down-regulated (SLR<-2). When pericancerous epithelium was compared with normal gastric mucosa, 64 genes were found, with a difference of more than four times in expression levels. Of the 64 genes, 50 were up-regulated (SLR>2), and 14 were down-regulated (SLR<-2). Compared with normal gastric mucosa, a total of 143 genes with a difference in expression levels (more than four times, either in cancer or in pericancerous epithelium) were found in gastric cancer (T) and pericancerous epithelium (P). Of the 143 genes, 108 were up-regulated (SLR>2), and 35 were down-regulated (SLR<-2). CONCLUSION: To apply a gene chip could find 143 genes associated with the genes of gastric cancer in pericancerous epithelium, although there were no pathological changes in the tissue slices. More interesting, six genes of pericancerous epithelium were up-regulated in comparison with genes of gastric cancer and three genes were down-regulated in comparison with genes of gastric cancer. It is suggested that these genes may be related to the carcinogenesis and development of early gastric cancer.

[Characterization of human lung cancer cell line A549 transfected with human interferon-gamma gene].

OBJECTIVE: To establish a human lung cancer cell line expressing human interferon-gamma. METHODS: The full-length gene of human interferon-gamma (IFN-gamma) was introduced into the human lung adenocarcinoma cell line A549 through retroviral vector pLXSN. The established cell line A549-IFN-gamma was tested for expression of MHC class I and class II by flow cytometer (FCM) and tested for expression of IFN-gamma by enzyme-lined immunoadsorbent assay (ELISA ). The tumorigenesis of cell line A549-IFN-gamma was tested on nude mice. RESULTS: A high level of IFN-gamma protein was detected in the culture supernatants of cell line A549-IFN-gamma. The expressions of MHC class I and class II on A549-IFN-gamma cells increased significantly (P<0.01), when compared with parental cell line A549. However, there was no significant difference (P<0.05) between the growth of cell line A549-IFN-gamma and A549. Finally, the tumorigenesis test showed that A549-IFN-gamma had lower tumorigenetic effects than A549. CONCLUSION: The results indicate that introduction of human IFN-gamma gene into cell line A549 could increase its immunogenicity and decrease its tumorigenesis. With the established cell line A549-IFN-gamma, a tumor vaccine for human lung cancer may be developed.

Difference of gene expression profiles between esophageal carcinoma and its pericancerous epithelium by gene chip.

AIM: To study the difference of gene expression between esophageal carcinoma and its pericancerous epithelium and to screen novel associated genes in the early stage of esophageal carcinogenesis by cDNA microarray. METHODS: Total RNA was extracted with the original single step way from esophageal carcinoma, its pericancerous epithelial tissue and normal esophageal epithelium far from the tumor. The cDNA retro-transcribed from equal quantity of mRNA was labeled with Cy5 and Cy3 fluorescence functioning as probes. The mixed probes were hybridized with two pieces of BioDoor 4 096 double dot human whole gene chip. Fluorescence signals were scanned by ScanArray 3 000 laser scanner and farther analyzed by ImaGene 3.0 software with the digital computer. RESULTS: (1) A total of 135 genes were screened out, in which 85 and 50 genes whose the gene expression levels (fluorescence intensity) in esophageal carcinoma were more than 2 times and less than 0.5 times respectively compared with the normal esophageal epithelium. (2) There were also total 31 genes, among then 27 and 4 whose expressions in pericancerous tissue were 2-fold up-regulated and 0.5-fold down-regulated respectively compared with normal esophageal epithelium. (3) There were 13 genes appeared simultaneously in both pericancerous epithelium and esophageal carcinoma, while another 18 genes existed in pericancerous epithelium only. CONCLUSION: With the parallel comparison among these three gene profiles, it was shown that (1). A total of 135 genes, Whose expression difference manifested as fluorescence intensity were more than 2 times between esophageal carcinoma and normal esophageal epithelium, were probably related to the occurrence and development of the esophageal carcinoma. (2). The 31 genes showing expression difference more than 2 times between pericancerous and normal esophageal epithelium might be relate to the promotion of esophageal pericancerosis and its progress. The present study illustrated that by using the gene chip to detect the difference of gene expression profiles might be of benefit to the gene diagnosis, treatment and prevention of esophageal carcinoma.

[The role of cortical microtubules in moss protonemal cells during dehydration/rehydration cycle].

Plant cells response to water deficit through a variety of physiological processes. In this work, we studied the function of microtubule cytoskeleton during dehydration/rehydration cycle in moss (Atrichum undulatum) protonemal cells as a model system. The morphological and cytological change of protonemal cells during dehydration and rehydration cycle were first investigated. Under normal conditions, protonemal cells showed bright green colour and appeared wet and fresh. Numerous chloroplasts distributed regularly throughout the cytoplasm in each cell. After dehydration treatment, protonemal cells lost most of their chlorophylls and turned to look yellow and dry. In addition, dehydration caused plasmolysis in these cells. Upon rehydration, the cells could recover completely from the dehydrated state. These results indicated that moss had a remarkable intrinsic ability to survive from the extreme drought stress. Microtubule, an important component of cytoskeleton, is considered to play crucial roles in the responses to some environmental stresses such as cold and light. To see if it is also involved in the drought tolerance, dynamic organization of microtubules in protonemal cells of Atrichum undulatum subjected to drought and rehydration were examined by indirect immunofluorescence combined with confocal lasersharp scanning microscopy. The cortical microtubules were arranged into a fine structure with a predominant orientation parallel to the long axis of the cells in the control cells. After dehydration, the microtubule organization was remarkablly altered and the fine microtubule structure disappeared whereas some thicker cables formed. When the cells were grown under rehydration conditions, the fine microtubule arrays reappeared. These results provided a piece of evidence that microtubules play a role in the cellular responses to drought stress in moss. Furthermore, we analyzed the effects of the microtubule-disrupting agent colchicine on the morphology recovery of the protonemal cells during rehydration process. The cells were incubated with colchicine, followed by drought stress treatment and rehydration in the presence of colchicine to prevent recovery of microtubule organization. Results from immunofluorescence showed that microtubule arrays were broken down into smaller fragments. Compared to the cells treated with drought stress alone, the cells treated with drought stress in the presence of colchicine could not recover after rehydration treatment. The morphology resembled those of the drought treated cells, with obvious plasmolysis phenomena and loss of chlorophyll content. These results support the notion that microtubules were involved in the deccication tolerance mechanism in Atrichum undulatum.