RESUMO
A cDNA encoding a putative aquaporin was cloned from the ovaries of the American dog tick, Dermacentor variabilis (Say) (Acari: Ixodidae). The encoded protein is most similar to the vertebrate aquaporin 9 protein family. Localization by reverse transcription-polymerase chain reaction (RT-PCR) shows expression in the gut and ovaries of adult females but not in the synganglion, Malpighian tubules, or salivary glands. Quantitative RT-PCR indicates that it is primarily expressed in the ovaries, with approximately 146 times more transcript than in the gut. When expressed in Xenopus oocytes, the aquaporin-like protein localized to the plasma membrane.
Assuntos
Aquaporinas/isolamento & purificação , Trato Gastrointestinal/química , Proteínas de Insetos/isolamento & purificação , Ixodidae/química , Ovário/química , Sequência de Aminoácidos , Animais , Aquaporinas/análise , Aquaporinas/classificação , Sequência de Bases , Feminino , Regulação da Expressão Gênica , Proteínas de Insetos/análise , Proteínas de Insetos/classificação , Ixodidae/metabolismo , Dados de Sequência Molecular , Oócitos , Transporte Proteico , XenopusRESUMO
We have cloned the fire ant glucose transporter 8 (GLUT8) cDNA providing the first molecular characterization of a GLUT8 in insects. Glucose is a poly-alcohol and, due to its high hydrophilicity, cannot move across cell membranes. GLUT8 is a putative facilitative transporter for the cellular import and export of glucose. The complete 2,974-bp cDNA encodes a 501-residue protein with a predicted molecular mass of 54.8 kDa. Transcripts were detected in the brain, midgut, hindgut, Malpighian tubule, fat body, ovary, and testis. The highest transcriptional expression was found in fat body. Northern blot analysis revealed different transcript sizes in mated queen brains, alate female ovaries, and male testes. We propose that four other sequences obtained from insect genome projects from the honey bee Apis mellifera (ENSAPMP00000006624), the malaria mosquito Anopheles gambiae (EAA11842), and the fruit fly Drosophila melanogaster (AAQ23604 and AAM52591) are likely the orthologues of the fire ant GLUT8. Phylogenetic relationships in insect glucose transporters are presented.