| Chordoma, a frequent malignant tumor of bone, is usually adult epithelial tumors arising from embryonic notochord remains of the axial skeleton. Thus, the tumor presents as a midline mass predominantly occurring in the sacrococcy-geal or shenooccipital regions. Chordoma is slowly growing tumor with a locally aggressive growth pattern. This invasive growth, accompanied by extensive local bone destruction, is responsible for the high recurrence rate of the tumor. Many published papers discussed its clinic characteristic points,but little is known a-bout the molecular changes in this disease. Few protooncogenes and tumor sup-presser genes have been found to be altered in chordoma. Discovery and study of novel genes related to chordoma helps to understand the molecular mechanisms better in the development of chordoma.This paper consists of two parts. Cloning, sequencing and identifying two novel cDNA fragments related to chordoma are described in the first part and expression of FHIT gene in chordoma is in the second part.The First Part Cloning, sequencing and identifying two novel cDNAfragments related to chordomaIntroductionIn this study, we use DD - PCR and RT - PCR to clone, sequence and i-dentify genes related to chordoma.Materials And MethodsIn this study, we perform 18 cases of chordoma tissue and its normal tissue around them as materials. Genomyx Fluoro DD kits are from BECKMAN compa-ny, USA. Other reagents are from GIBCOBRL,TaKaRa and Promega Corp. We also use GenomyxLR?DNA Sequencer Electrophoresis System ( GX100) and the Genomyx SC?Fluorescent Imaging Scanner (FL100-4) from BECKMAN corp. We follow the methods of Genomyx' s to do our DD - PCR.ResultsAfter DD - PCR, we have two novel cDNA fragments and their nucleotide sequences. A homology search of these two cDNA fragments, we know that they are RNF - 11 and CTC-50DM5 gene. We designed double special primers for a RT - PCR to detect our results, and the result was similar to DD - PCR. Then we detected all tissues using RT - PCR and found that RNF - 11 gene express highly in normal tissue and CTC -50DM5 be in contract.DiscussionIn the process of development, differentiation and metabolism, the differential expression of genes plays a pivotal role. mRNA differential display, established by Liang and Pardee in 1992, is among the most sensitive methods for the isolation of differentially regulated mRNA. In short , mRNA is reverse transcribed into corresponding cDNA, then cDNA is amplified by PCR and displayed on 6% PAG gels. This simple, yet powerful technique provides essentially complete screening of the mRNA pools of related cell types for qualitative and quantitative differences in specific mRNA species. DD analysis can simultaneously detect both upregulated and downregulated mRNAs, and allows multiple sample screening simultaneously. By comparing the relative mRNA profiles of different cell populations, conclusions can be drawn concerning the effects of various parameters on gene expression, and the concomitant effects of these changes in expression upon cellular physiology and morphology. With the modification of the method, the technique of differential display( DD) has become a very useful method for elucidating changes in gene expression in response to temporal de-velopment, disease and mitogenic stimulants.Liang P using DD - PCR to compare normal breast cell with breast cancer cell,he found SI and S2 gene expressing in normal breast cell ,then M gene only expressing in breast cancer cell. Using transduction technique, Liang found mob - 1 gene was a downregulated signal of Ras gene, and it had significant similarity homology to IP - 10. Chen also using DD - PCR found a new gene -N8, which expressing highly in human lung cancer, including small cell lung cancer and non - small cell lung cancer than normal lung tissue. A Japanese researcher Shibahara cloned a new gene,MA-3 in apoptosis.In this study,we use Gynomyx DD system produced by BECKMAN company, USA. The anchored primers incorporate...
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