Gene Cloning and Expression Analysis of G Protein αq Subunit from Helicoverpa assulta (Guenée)

Molecular Cloning and Characterization of G Alpha Proteins from the Western Tarnished Plant Bug, Lygus hesperus

The Gα subunits of heterotrimeric G proteins play critical roles in the activation of diverse signal transduction cascades. However, the role of these genes in chemosensation remains to be fully elucidated. To initiate a comprehensive survey of signal transduction genes, we used homology-based cloning methods and transcriptome data mining to identity Gα subunits in the western tarnished plant bug (Lygus hesperus Knight). Among the nine sequences identified were single variants of the Gαi, Gαo, Gαs, and Gα12 subfamilies and five alternative splice variants of the Gαq subfamily. Sequence alignment and phylogenetic analyses of the putative L. hesperus Gα subunits support initial classifications and are consistent with established evolutionary relationships. End-point PCR-based profiling of the transcripts indicated head specific expression for LhGαq4, and largely ubiquitous expression, albeit at varying levels, for the other LhGα transcripts. All subfamilies were amplified from L. hesperus chemosensory tissues, suggesting potential roles in olfaction and/or gustation. Immunohistochemical staining of cultured insect cells transiently expressing recombinant His-tagged LhGαi, LhGαs, and LhGαq1 revealed plasma membrane targeting, suggesting the respective sequences encode functional G protein subunits.

Cloning and expression analysis of G-protein Gαq subunit and Gβ1 subunit from Bemisia tabaci Gennadius (Homoptera: Aleyrodidae)

The heterotrimeric G proteins play an essential role in a wide variety of signal transduction pathways, mediating the process of chemical signals from the environment in all higher eukaryotic organisms. In this article, two G-protein subunit genes encoding Gαq and Gβ1 were cloned from Bemisia tabaci Gennadius. The full-length cDNA sequence of BtGαq consisted of 2,336 bp with an ORF of 1,062 bp encoding 353 amino acids and BtGβ1 had a full length of 1,942 bp with an ORF of 1,023 nucleotides encoding 340 amino acids. The amino acid sequences of BtGαq and BtGβ1 from B. tabaci B biotype were identical to those from the Q biotype. Phylogenetic analysis identified G protein α and β subunit families from insects based on their amino acid sequences. The expression patterns of BtGαq and BtGβ1 at different development stages and in different body regions were analyzed by real-time quantitative PCR and Western blot. The results show that BtGαq and BtGβ1 are neither developmental stage-specific nor tissue-specific. The transcript levels of BtGαq in the B biotype are similar to that in the Q biotype, the transcript levels of BtGβ1 at egg, first instar and pupae in B biotype were significantly higher than that in Q biotype. The transcript levels of BtGαq and BtGβ1 in the head were significantly higher than those in thorax and abdomen indicating that they are involved in nervous system and sensory functions.

Cloning and expression analysis of a G-protein α subunit--Gαo in the rice water weevil Lissorhoptrus oryzophilus Kuschel

The open reading frame (ORF) encoding a novel G protein α subunit, Lo Gα(o), was cloned from the parthenogenetic rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae). The Lo Gα(o) ORF encodes a protein of 354 amino acid residues. The deduced protein sequence shares high homology with Gα(o) from other species. The expression patterns of Lo Gα(o) in various adult tissues were indicated by real-time quantitative PCR and Western blot. The results showed that Lo Gα(o) mRNA was expressed at similar levels in tissues except relative high levels in the antennae of adult, and Lo Gα(o) protein of an apparent molecular mass of about 40 kDa was expressed in various tissues of the adult. Immunocytochemical localization showed that Lo Gα(o) was mainly expressed in the dendrites of the trichoid sensilla in the antenna of the weevil. The tissue and cellular localization of Lo Gα(o) suggests that Lo Gα(o) may take a part in signal transduction of olfactory/gustatory.