SCREENING FOR MUTATIONS IN A NOVEL RETINAL - SPECIFIC GENE AMONG CHINESE PATIENTS WITH RETINITIS PIGMENTOSA

Objective. To identify and evaluate mutations in the RPl gene among Chinese patients with retinitis pigmen-tosa (RP).Methods. Leukocyte DNA of 92 RP patients were collected in Hong Kong. Sequence changes of the entire coding region of the RP1 gene were examined using PCR, conformation sensitive gel electrophoresis and DNA sequencing.Results. In total, 1 nonsense mutation and 1 nonsense variant as well as 10 missense alterations were identified in the RP1 gene, among which, Arg677Ter was found in 1 RP patient and another nonsense variant, Argl933Ter, was identified in 3 normal individuals and 1 patient with Stargardt' s disease, suggesting its nonpathogenicity. Arg677Ter is expected to lead to large disruptions of the encoded protein.Conclusions. The nonpathogenicity of Argl933Ter indicates that the C - terminal 224 residues of RPl protein may be not critical for RP1. The most C - terminal truncation previously reported was due to Tyr1053 (1 -bp del) and occurred in RP patients. Thus RP can be caused by reduction in the level of the region of RPl protein after codon 1052 but before 1933. To ascertain such a proposition, genotypes of more RP patients may reveal more RP causative mutations and more sequence alterations different than those of other ethnic groups.

Experimental research for specific down-regulated expression of p53 gene by individual antisense RNA in vitro

Objective： To investigate the specific blockage effect of individual antisense RNA on mutant p53 gene in vitro. Methods： The single strand antisense transcription system containing mt-p53 exon 8 sequence （pGEM3zf（＋/-）p53exon8） was constructed. The ligation of antisense RNAwith mt-p53 gene was confirmed by in situ hybridization; MDA-MB-231 human breast cancer cells were transfected with ASp53exon8＇RNA cotionic liposome-mediated. Expression of mt-p53 protein was examined by immunocytochemical staining and Western blot. Cell proliferation was evaluated by MTT assay; Cell cycle distribution was determined by flow cytometry （FCM）; Apoptosis was observed by TUNEL. Results： In transfected MDA-MB-231 cells, hybridization signals were observed in cytoplasm. ASp53exon8＇RNA transfection induced inhibition of cell proliferation, G2/M phase arrest and increasing apoptotic rates. In addition, expression of p53 protein was down-regulated. Conclusion： pGEM3zf（＋/-）p53exon8 was well constructed and ASp53exon8＇RNA can block mt-p53 gene expression specifically and then inhibit MDA-MB-231 cell proliferation in vitro, which may serve as therapeutic means for human malignancy.

Detecting Factor Ⅺ Deficiency in Holstein Cattle Using PCR Analysis

[Objective] This study established a method to detect Factor Ⅺ by polymerase chain reaction analysis.[Method]A pair of primers was designed and synthesized according to sequences of FⅪ gene in Holstein calves,published in Genbank. Polymerase chain reaction was used to analyze FⅪ deficiency of 576 Holstein calves in Henan,and the result was verified by DNA sequencing. [Result] We detect 576 cows,which include two carriers and one F Ⅺ deficiency,and the result was consistent with the DNA sequencing. The frequency of the FⅪ mutant allele was 0.3%,the carrier was 0.3%,the prevalence was 0.2%.[Conclusion]A method detecting FⅪ by polymerase chain reaction analysis was established. This method is not only simple and convenient,but also has a high accuracy and low cost,which is more suitable for large-scale FⅪ investigation.