Loss of Posterior Silk Gland Transcription Specificity of Fibroin Light Chain Promoter due to Absence of 41 bp Sequence Containing Possible Inhibitor Binding Sites  

作　　者：Ting-Qing GUO Jian-Yang WANG Sheng-Peng WANG Xiu-Yang GUO Ke-Wei HUANG Jun-Ting HUANG Chang-De LU 

机构地区：[1]Institute of Biochemistry, and Cell Biology. Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China [2]Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China [3]Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China

出　　处：《Acta Biochimica et Biophysica Sinica》2005年第12期819-825, ,共7页生物化学与生物物理学报（英文版）

基　　金：supported by the grants from the National NaturalScience Foundution of China(No.30370326.No.30470350)

摘　　要：The gene encoding fibroin light chain protein （FibL） is specifically expressed in the posterior silk gland of silkworm and repressed in other tissues. The binding sites of several transcription factors involved in the silk gland transcription specificity offibl promoter have been recognized, including SGFB, PSGF and BMFA. Here we report the leak expression of the enhanced green fluorescent protein （EGFP） reporter gene in tissues other than the posterior silk gland in vivo when under the control of a shortenedfibl promoter with deletion of the 5＇ terminal 41 bp sequence, which is located at -650 nt to -610 nt upstream of thefibl transcription starting site. Assay of silk gland specificity of the promoters was performed by observation of green fluorescence in tissues of silkworm larvae following inter-haemocoelic injection of recombinant Autographa californica multiple nuclear polyhedrosis virus carrying the EGFP reporter gene controlled by different lengths offibl promoters. Our results indicated that availability of the binding sites of several known factors, including SGFB, PSGF and BMFA, is not sufficient for intact silk gland transcription specificity of fibl promoter, and there are possible inhibitor binding sites in the 41 bp sequence （-650 nt to -610 nt） upstream of the transcription starting site which may be required to repress the activity offibl promoter in other tissues.The gene encoding fibroin light chain protein （FibL） is specifically expressed in the posterior silk gland of silkworm and repressed in other tissues. The binding sites of several transcription factors involved in the silk gland transcription specificity offibl promoter have been recognized, including SGFB, PSGF and BMFA. Here we report the leak expression of the enhanced green fluorescent protein （EGFP） reporter gene in tissues other than the posterior silk gland in vivo when under the control of a shortenedfibl promoter with deletion of the 5＇ terminal 41 bp sequence, which is located at -650 nt to -610 nt upstream of thefibl transcription starting site. Assay of silk gland specificity of the promoters was performed by observation of green fluorescence in tissues of silkworm larvae following inter-haemocoelic injection of recombinant Autographa californica multiple nuclear polyhedrosis virus carrying the EGFP reporter gene controlled by different lengths offibl promoters. Our results indicated that availability of the binding sites of several known factors, including SGFB, PSGF and BMFA, is not sufficient for intact silk gland transcription specificity of fibl promoter, and there are possible inhibitor binding sites in the 41 bp sequence （-650 nt to -610 nt） upstream of the transcription starting site which may be required to repress the activity offibl promoter in other tissues.

关 键 词：promoter specificity fibroin light chain SILKWORM Bombyx mori recombinant AcMNPV 

分 类 号：Q51[生物学—生物化学]