Biomedical subjects

Jian-Chiuan Li

Publications and source records attributed to Jian-Chiuan Li.

3 recordsLinked to original sources

PubMed2005

Differential expression of osteoblast-specific factor 2 and polymeric immunoglobulin receptor genes in nasopharyngeal carcinoma.

BACKGROUND: The molecular mechanisms leading to development of nasopharyngeal carcinoma (NPC) are not well understood. To delineate the features of NPC, we tried to identify unique expression of cellular genes in the tumor biopsy specimens. METHODS AND RESULTS: By use of a combination of differential display and cDNA microarray analysis, we found two genes, 3E5 and 4A5, to show unique expression in the NPC biopsy specimens compared with nontumor nasopharyngeal tissues. Expression of 3E5, the osteoblast-specific factor-2 (OSF-2) gene, was detected at significantly higher levels in NPC biopsy specimens than that in control tissues, a finding confirmed using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). A correlation between expression of OSF-2 and its regulatory cytokine transforming growth factor-beta was observed in nontumor tissues but not in NPC biopsy specimens. On the other hand, expression of 4A5, whose sequences represent the 3' untranslated region of the polymeric immunoglobulin receptor (pIgR) gene, was detected rarely in NPC specimens but frequently in nontumor controls. The expression of pIgR in normal epithelial cells, but not in NPC tumor cells, was verified by RT-PCR and immunohistochemical staining. CONCLUSIONS: NPC shows significant upregulation of OSF-2 and downregulation of pIgR. Expression of OSF-2 is likely to play a role in the pathogenesis of NPC. In addition, expression of OSF-2 and pIgR is disassociated with the expression of their regulatory cytokines in NPC biopsy specimens, suggesting that the tumors may have altered responses to certain cytokines.

Cell Adhesion Molecules↗

PubMed2004

Genomic shotgun array: a procedure linking large-scale DNA sequencing with regional transcript mapping.

To facilitate transcript mapping and to investigate alterations in genomic structure and gene expression in a defined genomic target, we developed a novel microarray-based method to detect transcriptional activity of the human chromosome 4q22-24 region. Loss of heterozygosity of human 4q22-24 is frequently observed in hepatocellular carcinoma (HCC). One hundred and eighteen well-characterized genes have been identified from this region. We took previously sequenced shotgun subclones as templates to amplify overlapping sequences for the genomic segment and constructed a chromosome-region-specific microarray. Using genomic DNA fragments as probes, we detected transcriptional activity from within this region among five different tissues. The hybridization results indicate that there are new transcripts that have not yet been identified by other methods. The existence of new transcripts encoded by genes in this region was confirmed by PCR cloning or cDNA library screening. The procedure reported here allows coupling of shotgun sequencing with transcript mapping and, potentially, detailed analysis of gene expression and chromosomal copy of the genomic sequence for the putative HCC tumor suppressor gene(s) in the 4q candidate region.

Cell Line, Tumor↗

PubMed2003

Comparative genome analysis of Vibrio vulnificus, a marine pathogen.

The halophile Vibrio vulnificus is an etiologic agent of human mortality from seafood-borne infections. We applied whole-genome sequencing and comparative analysis to investigate the evolution of this pathogen. The genome of biotype 1 strain, V. vulnificus YJ016, was sequenced and includes two chromosomes of estimated 3377 kbp and 1857 kbp in size, and a plasmid of 48,508 bp. A super-integron (SI) was identified, and the SI region spans 139 kbp and contains 188 gene cassettes. In contrast to non-SI sequences, the captured gene cassettes are unique for any given Vibrio species and are highly variable among V. vulnificus strains. Multiple rearrangements were found when comparing the 5.3-Mbp V. vulnificus YJ016 genome and the 4.0-Mbp V. cholerae El Tor N16961 genome. The organization of gene clusters of capsular polysaccharide, iron metabolism, and RTX toxin showed distinct genetic features of V. vulnificus and V. cholerae. The content of the V. vulnificus genome contained gene duplications and evidence of horizontal transfer, allowing for genetic diversity and function in the marine environment. The genomic information obtained in this study can be applied to monitoring vibrio infections and identifying virulence genes in V. vulnificus.

Amino Acid Sequence↗