Functional Identification of the Transcription Start Site and the Core Promoter of the Juvenile Hormone Esterase Gene in Trichoplusia ni

Abstract

The juvenile hormone (JH) esterase gene in T. ni encodes a protein that is responsible for the degradation of JH. The 5′ structural characterization of this JH-sensitive gene was accomplished using reverse transcription PCR (RT-PCR) and northern analysis. The transcriptional start site of the JHE gene was biochemically determined by two methods: a 5′ rapid amplification of cDNA ends (RACE) procedure which produced independent products with a sequence identical to the sequence of an exon encoded 5′ to the putative first intron and by northern analysis with intronic and exonic probes. Both the transcription start site and the region containing the core promoter were also functionally identified by use of an in vitro transcription assay. The product of the in vitro transcription reaction, under the control of the putative core promoter region, initiated at the same base as identified by the RACE procedure, whether the reaction was driven by lepidopteran or by dipteran nuclear extracts. This result is the first functional identification of the core promoter region and transcription start site of any JH-sensitive gene.