Abstract:

Abstract:Objective To study the effects of different protosilencers on gene silencing and the  reasons of differences of gene silencing. Methods HML-I silencer was replaced by different protosilencers. The expression level of reporter gene and the structure of chromosome were compared with or without HML-E. Results After deleting HML-E silencer and replacing HML-I with RAP1p,ORC and Abflp respectively,the cells grew similarly inSC-ura and SC+FOA plate. When HML-E exited,the cells grew similarly on SC-ura plate after replacing HML-I with RAP1p,ORC and ABF1 respectively. The cells were unable to grow on FOA plate when HML-I was replaced with Raplp,However,the cells grew on FOA plate when HML-I was replaced with ORC or ABF1.The micrococcal nuclease digestion data showed that the cells which HML-I was replaced with ORC or ABF1presented similar specific bands to which HML-I was replaced by HMR-E. Conclusion Protosilencers can’t silence gene in activated and basal expression independently,but it can do it with the help of silencer protosilencer. The differences in chromatin structure might be the reason for the difference of gene silencing.

Key words: gene silencing;silencer;protosilencer;micrococcal nuclease