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Zhen Lin

Publications and source records attributed to Zhen Lin.

24 records · Page 2Linked to original sources
PubMed2003

Nitric oxide synthase expression in human bladder cancer and its relation to angiogenesis.

Nitric oxide (NO) is synthesized by the enzyme family of nitric oxide synthases (NOS) and plays an important role in tumor growth and angiogenesis. The expression of two of the NOS isoforms, the endothelial and inducible isoforms (eNOS and iNOS, respectively), were evaluated in bladder tissue from patients with transitional cell carcinoma (TCC). The specimens were procured from 58 patients with TCC and 14 cases of normal bladder mucosa were used as a control group. NOS immunohistochemistry was performed and microvessal density (MVD) was determined. iNOS specific proteins were found in 47 of 58 bladder cancer specimens but not in control bladder tissue. The endothelial cells in both normal urothelium and tumor tissue showed a highly positive eNOS immunostaining. The MVD was 39.3+/-19.5 and 29.3+/-10.5 in TCC positive and negative for iNOS, respectively ( P<0.01). A correlation between iNOS immunoreactivity and tumor grade in bladder carcinoma could not be verified. These results indicate that NO generation from iNOS in the malignant epithelium and from eNOS in tumor stroma play a important role in tumor angiogenesis.

Adult↗
PubMed2003

The RNA-binding SAM domain of Smaug defines a new family of post-transcriptional regulators.

Anteroposterior patterning in Drosophila melanogaster is dependent on the sequence-specific RNA-binding protein Smaug, which binds to and regulates the translation of nanos (nos) mRNA. Here we demonstrate that the sterile-alpha motif (SAM) domain of Smaug functions as an RNA-recognition domain. This represents a new function for the SAM domain family, which is well characterized for mediating protein-protein interactions. Using homology modeling and site-directed mutagenesis, we have localized the RNA-binding surface of the Smaug SAM domain and have elaborated the RNA consensus sequence required for binding. Residues that compose the RNA-binding surface are conserved in a subgroup of SAM domain-containing proteins, suggesting that the function of the domain is conserved from yeast to humans. We show here that the SAM domain of Saccharomyces cerevisiae Vts1 binds RNA with the same specificity as Smaug and that Vts1 induces transcript degradation through a mechanism involving the cytoplasmic deadenylase CCR4. Together, these results suggest that Smaug and Vts1 define a larger class of post-transcriptional regulators that act in part through a common transcript-recognition mechanism.

Amino Acid Sequence↗
PubMed2002

Systematic identification of protein complexes in Saccharomyces cerevisiae by mass spectrometry.

The recent abundance of genome sequence data has brought an urgent need for systematic proteomics to decipher the encoded protein networks that dictate cellular function. To date, generation of large-scale protein-protein interaction maps has relied on the yeast two-hybrid system, which detects binary interactions through activation of reporter gene expression. With the advent of ultrasensitive mass spectrometric protein identification methods, it is feasible to identify directly protein complexes on a proteome-wide scale. Here we report, using the budding yeast Saccharomyces cerevisiae as a test case, an example of this approach, which we term high-throughput mass spectrometric protein complex identification (HMS-PCI). Beginning with 10% of predicted yeast proteins as baits, we detected 3,617 associated proteins covering 25% of the yeast proteome. Numerous protein complexes were identified, including many new interactions in various signalling pathways and in the DNA damage response. Comparison of the HMS-PCI data set with interactions reported in the literature revealed an average threefold higher success rate in detection of known complexes compared with large-scale two-hybrid studies. Given the high degree of connectivity observed in this study, even partial HMS-PCI coverage of complex proteomes, including that of humans, should allow comprehensive identification of cellular networks.

Amino Acid Sequence↗
PubMed2002

[Cloning and expression of extracellular domain of prostate specific membrane antigen in Escherichia coli and preparation of polyclonal antibody].

Human Prostate Specific Membrane Antigen(PSMA) cDNA was amplified using total RNA extracted from prostate carcinoma tissue by RT-PCR. The cDNA fragment of extracellular domain of PSMA(edPSMA) gene was amplified by PCR and cloned into expression vector pMAL-c2x. Sequence analysis of both PSMA and edPSMA revealed identity to the GenBank reported. The edPSMA was expressed in E. coli as part of a fusion protein with MBP as the induction of IPTG. Western blot analysis showed the recombinant protein could react with PSMA monocloned antibodies 4G5. MBP-edPSMA fusion protein were purified by amylose resin affinity chromatography and showed to be homogeneity in SDS-PAGE(120 kD). BALB/C mice were immunized with the purified protein for the preparation of polyclonal antibody. The polyclonal antibody, which had a title of 1:12,800, were indicated the specificity to prostate tissue.

Animals↗
PubMed2002

Using binning to maintain confidentiality of medical data.

Biomedical informatics in general and pharmacogenomics in particular require a research platform that simultaneously enables discovery while protecting research subjects' privacy and information confidentiality. The development of inexpensive DNA sequencing and analysis technologies promises unprecedented database access to very specific information about individuals. To allow analysis of this data without compromising the research subjects' privacy, we must develop methods for removing identifying information from medical and genomic data. In this paper, we build upon the idea that binned database records are more difficult to trace back to individuals. We represent symbolic and numeric data hierarchically, and bin them by generalizing the records. We measure the information loss due to binning using an information theoretic measure called mutual information. The results show that we can bin the data to different levels of precision and use the bin size to control the tradeoff between privacy and data resolution.

Algorithms↗