INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Molecular and functional characterization of a juvenile hormone acid methyltransferase expressed in the corpora allata of mosquitoes
Autor/es:
JAIME G. MAYORAL; MARCELA NOUZOVA; MICHIYO YOSHIYAMA; TETSURO SHINOD; SALVADOR HERNANDEZ-MARTINEZ; ELENA DOLGHIH; ADRIAN G. TURJANSKI; ADRIAN E. ROITBERG; HORACIO PRIESTAP; MARIO PEREZ; LUCY MACKENZIE; YIPING LI; FERNANDO G. NORIEGA
Revista:
INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY
Referencias:
Año: 2009 vol. 39 p. 31 - 37
ISSN:
0965-1748
Resumen:
A juvenile hormone acid methyltransferase (JHAMT) was isolated as an
abundant EST in a library of the corpora allata of the adult female
mosquito Aedes aegypti. Its full length cDNA encodes a 278-aa protein that has 43% amino acid identity with BmJHAMT, a juvenile hormone acid methyltransferase previously cloned from Bombyx mori.
Heterologous expression produced a recombinant protein that metabolizes
farnesoic acid (FA) into methyl farnesoate, as well as juvenile hormone
acid into juvenile hormone III (JH III) with exquisite stereo
specificity. Real time PCR experiments showed that JHAMT mRNA levels
are not an unequivocal indicator of JH III synthesis rates; the A. aegypti
JHAMT gene, silent in female pupae, was transcriptionally activated
just 46 h before adult eclosion. Radiochemical methyltransferase
assays using active and inactive corpora allata glands (CA) dissected
from sugar and blood-fed females respectively, clearly indicated that
significant levels of JHAMT enzymatic activity are present when the CA
shows very low spontaneous rates of JH III synthesis. Having the last
enzymes of the JH synthetic pathway readily available all the time
might be critical for the adult female mosquito to sustain rapid
dynamic changes in JH III synthesis in response to nutritional changes
or peripheral influences, such as mating or feeding. These results
suggest that this gene has different roles in the regulation of JH
synthesis in pupal and adult female mosquitoes, and support the
hypothesis that the rate-limiting steps in JH III synthesis in adult
female mosquitoes are located before entrance of FA into the synthetic
pathway.