G. Jayachandran et Am. Fallon, Evidence for expression of EcR and USP components of the 20-hydroxyecdysone receptor by a mosquito cell line, ARCH INS B, 43(2), 2000, pp. 87-96
The reverse transcriptase polymerase chain reaction (RT-PCR) was used to ex
amine whether the C7-10 cell line from the mosquito, Aedes albopictus, expr
esses transcripts encoding 20-hydroxyecdysone receptor (EcR) and ultraspira
cle (USP) isoforms known to constitute a functional 20-hydroxyecdysone rece
ptor. Here we describe recovery and analysis of products with high similari
ty to the EcR and to the USP isoform "a" that have been reported from the r
elated mosquito, Aedes aegypti. The C7-10 EcR was 97% identical to Aedes ae
gypti EcR in amino acid sequence. Key features of the nuclear/steroid hormo
ne receptor superfamily, including the zinc fingers, proximal (P)-box, and
distal (D)-box were well conserved. However, the C7-10 EcR contained 5 addi
tional amino acids in the C-terminal domain F, which required introduction
of gaps to maximize alignment. The 5'-untranslated regions of the two mosqu
ito EcRs were 98% identical, but the function of this region remains unknow
n. The C7-10 USP was 95% identical in amino acid sequence to the longer Aed
es aegypti isoform "a." Although only the C7-10 EcR was detected on Norther
n blots using total RNA from the cell line, transcripts for both EcR and US
P were detected using the RT-PCR procedure. These transcripts appeared to b
e expressed constitutively and expression levels were not affected by treat
ment of cells with 20-hydroxyecdysone. (C) 2000 Wiley-Liss, Inc.