Abstract: Objective To identify LongSAGE Tags in systemic lupus erythematosus (SLE) by generation of longer cDNA fragments from serial analysis of gene expression (SAGE) tags for gene identification(GLGI).Methods CD4⁺ and CD8⁺ T lymphocytes were collected from the PBMCs of 25 patients with SLE and 10 healthy controls.Then the total RNA was extracted and reverse transcribed to cDNA.After that,PCR was performed with the cDNA as plate,a 17-base tag as the sense primer,and a single base anchored oligo(dT)as the antisense primer.With the GLGI approach,the IongSAGE tags were converted into their corresponding 3'end of cDNA fragments covering hundreds of bases,which were identified by DNA cloning and sequencing.Results Nine of twelve tags matching a specific single gene were stably and efficiently extended,including the primary 17-bp SAGE tag sequence.And their long fragments had a consistency of more than 85% with the corresponding known sequences,which suggested that these tags originated from the known genes.No new genes were found in 20 non-matching genes.Conclusion GLGI technology can efficiently identify the genes from LongSAGE,and the combined application of LongSAGE and GLGI is a good method for large-scale identification of SAGE tags.

Key words: Lupus erythematosus, systemic, GLGI, LongSAGE