THAP and ATF-2 regulated sterol carrier protein-2 promoter activities in the larval midgut of the yellow fever mosquito, Aedes aegypti.
Expression of sterol carrier protein-2 (SCP-2) in Aedes aegypti shows a distinct temporal/spatial pattern throughout the life cycle. In order to identify the transcription factors responsible for the larval temporal/spatial regulation of AeSCP-2 transcription, AeSCP-2 promoter activities were studied in vivo via transient transfection of promoter/reporter gene assays. Regulatory sequences upstream -1.3 kb of the transcription start site of AeSCP-2 were found to be critical for the in vivo temporal/spatial promoter activity. Interestingly, the -1.6 kb promoter sequence efficiently drove the larval midgut-specific siRNA expression, indicating that the -1.6 kb upstream sequence is sufficient for temporal/spatial AeSCP-2 transcriptional activity. Four transcription factors were identified in the midgut nuclear extract from feeding larvae via labeled -1.6/-1.3 kb DNA probe pull-down and proteomic analysis. Co-transfection of the promoter/reporter gene with inducible siRNA expression of each transcription factor was performed to confirm the regulatory function of individual transcription factor on AeSCP-2 transcriptional activities in the larval midgut. The results indicate that two of the identified transcription factors, Thanatos-associated protein (THAP) and activating transcription factor-2 (ATF-2), antagonistically control AeSCP-2 transcriptional activity in the midgut of feeding larvae via the regulatory sequences between -1.6 to -1.3 kb 5' upstream of the transcription start site. In vivo expression knockdown of THAP and ATF-2 resulted in significant changes in developmental progression, which may be partially due to their effects on AeSCP-2 expression.
College of Life Sciences, Central China Normal University, Wuhan, Hubei, China. prhh@sina.com
Rong
R
Peng
Qiang
Q
Fu
Huazhu
H
Hong
Tyler
T
Schwaegler
Que
Q
Lan
D051698:Activating Transcription Factor 2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000330:Aedes / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D019476:Insect Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008297:Male; D011401:Promoter Regions, Genetic; D062211:Spatio-Temporal Analysis
D051698:Activating Transcription Factor 2; D002352:Carrier Proteins; D019476:Insect Proteins; C072087:sterol carrier proteins