Objective:To isolate and identify the genes related to slow growth mutants of human lymphoblastoid cell TK6.Methods:Human genome expression microarray was used to measure gene expression at different levels

thereby narrowing candidate gene locations and expression properties.Target genes were identified by retrieving candidate gene functions and verified by RT-PCR.Results:The overall expression level of slow growth mutant was down regulated

but with several chromosomal expressions up regulated.In the region of TK to telomere

TK gene and adjacent CBX2

CBX4

CBX8 were overexpressed;functional retrieving found that CBXs were inhibitors of transcription;CBXs functional verification experiment showed that CBX4 expression was positively associated with cell’s doubling time.Conclusion:The target genes related to slow growth mutant are CBXs located on chromosome 17 q arm near the telomere

but still more evidence is needed to confirm that CBXs are the most directly related genes to slow growth mutant.