The point mutation of p53 gene exon7 in hepatocellular carcinoma from Anhui Province,a non HCC prevalent area in China

AIM: In hepatocellular carcinoma (HCC) prevalent areas of China, the point mutation of p53 exon7 is highly correlated with Hepatitis B virus(HBV) infection and aflatoxin B intake. While in non-HCC-prevalent areas of China, these factors are not so important in the etiology of HCC. Therefore, the point mutation of p53 exon7 may also be different than that in HCC-prevalent areas of China. The aim of this study is to investigate the status and carcinogenic role of the point mutation of p53 gene exon7 in hepatocellular carcinoma from Anhui Province, a non-HCC-prevalent area in China. METHODS: PCR PCR-SSCP and PCR-RFLP were applied to analyze the homozygous deletion and point mutation of p53 exon7 in HCC samples from Anhui, which were confirmed by DNA sequencing and Genbank comparison. RESULTS: In the 38 samples of hepatocellular carcinoma, no homozygous deletion of p53 exon7 was detected and point mutations of p53 exon7 were found in 4 cases, which were found to be heterozygous mutation of codon 249 with a mutation rate of 10.53%(4/38). The third base mutation(G-T) of p53 codon 249 was found by DNA sequencing and Genbank comparison. CONCLUSION: The incidence of point mutation of p53 codon 249 is lower in hepatocellular carcinoma and the heterozygous mutation of p53 exon7 found in these patients only indicate that they have genetic susceptibility to HCC. p53 codon 249 is a hotspot of p53 exon7 point mutation, suggesting that the point mutation of p53 exon 7 may not play a major role in the carcinogenesis of HCC in Anhui Province, a non-HCC-prevalent area in China.

Rice bicoid-related cDNA sequence and its expression during early embryogenesis

Bicoid is one of the important Drosophila maternal genes involved in the control of embryo polarity and larvae segmentation. To clone and characterize the rice bicoid-related genes, one cDNA clone, Rb24 (EMBL accession number: AJ2771380), was isolated by screening of rice unmature seed cDNA library. Sequence analysis indicates that Rb24 contains a putative amino acid sequence, which is homologous to unique 8 amino acids sequence within Drosophila bicoid homeodomain (50% identity, 75% similarity) and involves a lys-9 in putative helix 3. Northern blot analysis of rice RNA has shown that this sequence is expressed in a tissue-specific manner. The transcript was detected strongly in young panicles, but less in young leaves and roots. This results are further confirmed with paraffin section in situ hybridization. The signal is intensive in rice globular embryo and located at the apical tip of the embryo, then, along with the development of embryo, the signal is getting reduced and transfers into both sides of embryo. The existence of bicoid-related sequence in rice embryo and the similarity of polar distribution of bicoid and Rb24 mRNA in early embryo development may implicates a conserved maternal regulation mechanism of body axis presents in Drosophila and in rice.

Sequencing, Expression and Diagnostic Application of the Nucleoprotein Gene of Xinjiang Hemorrhagic Fever Virus

In order to analyze the nucleoprotein (NP) gene of Crimean-Congo hemorrhagic fever virus (CCHFV), viral RNA was amplified by RT-PCR by using the proof-reading DNA polymerase to produce the complete NP gene. The PCR product was sequenced, analyzed for phylogenesis and cloned into the expression vector pET32a and the recombinant plasmid expressed in E.coli BL-21 with high yield. The primarily purified fused protein was used to coat ELISA plates for the detect antibodies. It was found the similarities between NP gene of BA88166 and other XHFVs in nucleotide level and amino acid contents were very significant, and the NP gene of BA88166 encoded a nucleoprotein with 482 amino acid and a deduced molecular weight (MW) of 54?kDa. Western blot assay showed that the fusion protein expressed in bacteria possessed good antigenicity. The results with ELISA for the detection of the human and animal sera collected in endemic areas were found to be in good accordance to the clinical diagnosis. It concluded that the relations of NP genes of XHFV BA88166 and other XHFVs appeared to be evolutionally close. The methodologies established in this study were accurate, specific, rapid and reproducible for the clinical examinations and epidemiological survey.

The intraspecific difference of the triose phosphate isomerase (tim) gene from Giardia lamblia

OBJECTIVE: To investigate the intraspecific difference of the triose phosphate isomerase (tim) gene from Giardia lamblia (G. lamblia). METHODS: Total genomic DNA of G. lamblia was extracted and partial fragments of the triose phosphate isomerase (tim) gene were amplified by polymerase chain reaction (PCR). All nucleotide sequences were analyzed by using a phylogenetic analysis, which was constructed with parsimony and Neighbor-joining (N-J) methods. RESULTS: A total of 124 variable sites (23% of all sequences detected) was defined, most of which were found at the silent sites of codons. Two similar phylogenetic trees were constructed, subdividing 16 Giardia isolates into two groups. CONCLUSION: The genetic diversity of G. lamblia appeared to be little affected by factors of both host and geography, while natural-selection played an important role in DNA molecular evolution level of the tim gene. The tim gene may be considered a very useful genetic marker of the population genetic structure of G. lamblia.

Telomerase activity analysis of esophageal carcinoma using microdissection-TRAP assay

OBJECTIVES: To investigate telomerase activity in esophageal squamous cell carcinoma (SCC) and its preneoplasia lesions, and to study the relationships between telomerase activity and cancer differentiation, cancer invasiveness, and lymphatic metastasis. METHODS: Telomerase activity in esophageal SCC tissues, adjacent dysplasia tissues and normal epithelia from the surgical edge were assessed by microdissection-TRAP (telomeric repeat amplification protocol)-silver staining assay. RESULTS: Telomerase activity was detected in 37 (82.2%) of 45 esophageal tumors, 23 (79.3%) of 29 dysplasias, and 2 (5%) of 40 normal epithelia. There was a significant difference in activity between dysplasia and normal epithelium, as well as between tumor and normal epithelium. Twenty-six (92.9%) of 28 tumors with lymphatic metastasis had detectable telomerase activity compared to 11 (64.7%) of 17 non-lymphatic metastasis tumors. These relationships were statistically significant (P

Polymorphisms and functions of the aldose reductase gene 5' regulatory region in Chinese patients with type 2 diabetes mellitus

OBJECTIVE: To screen the 5' regulatory region of the aldose reductase (AR) gene for genetic variabilities causing changes in protein expression and affecting the promoter function. METHODS: The screenings were carried out by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). All SSCP variants were submitted for DNA sequencing and inserted into the plasmid chloromycetin acetyl transferase (CAT) enhancer vector. The constructs were used to transfect Hela cells, and CAT assays were performed to assess promoter activity. Gel mobility shift and footprinting assays were also performed to determine the interaction between the DNA and nuclear proteins. RESULTS: Two polymorphisms, C (-106) T and C (-12) G, were identified in the regulatory region in 123 Chinese control subjects and 145 patients with type 2 diabetes mellitus. The frequencies of genotypes WT/WT, WT/C (-12) G and WT/C (-106) T were not significantly different between the subjects and patients. In the patients with and without retinopathy, frequencies of WT/C (-106) T were 31.5% and 17.5% (P 0.05) respectively. The total frequency of WT/C (-12) G and WT/C (-106) T in patients with retinopathy was 41.8%, significantly higher than that (20.0%) in patients without retinopathy (P