From development to biodiversity–Tribolium castaneum, an insect model organism for short germband development
ABSTRACT Insect embryogenesis is best understood in the fruit fly Drosophila. However, Drosophila embryogenesis shows evolutionary-derived features: anterior patterning is controlled by a highly derived Hox gene bicoid, the body segments form almost simultaneously and appendages develop from imaginal discs. In contrast, embryogenesis of the red flour beetle Tribolium castaneum displays typical features in anterior patterning, axis and limb formation shared with most insects, other arthropods as well as with vertebrates. Anterior patterning depends on the conserved homeobox gene orthodenticle, the main body axis elongates sequentially and limbs grow continuously starting from an appendage bud. Thus, by analysing developmental processes in the beetle at the molecular and cellular level, inferences can be made for similar processes in other arthropods. With the completion of sequencing the Tribolium genome, the door is now open for post-genomic studies such as RNA expression profiling, proteomics and functional genomics to identify beetle-specific gene circuits.
- SourceAvailable from: Gregor Bucher
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- "Because of the cuticular reduction accompanying the process, embryonic head defects can be interpreted only with difficulty in Drosophila. Tribolium exhibits an typical insect larval head with all typical appendages (Klingler 2004; Posnien et al. 2010; Schröder et al. 2008) and markers for specific head regions (Schinko et al. 2008). In addition, the Tribolium model is a representative of the most species-rich metazoan taxon, the Coleoptera, which represent one fourth of all described animals (Hunt et al. 2007), including many important pest species such as the boll weevil, corn rootworm, Colorado potato beetle and comprising species with intriguing evolutionary adaptations like the horns of horned beetles (Moczek et al. 2006). "
ABSTRACT: Insect gene function has mainly been studied in the fruit fly Drosophila melanogaster because in this species many techniques and resources are available for gene knock down and the ectopic activation of gene function. However, in order to study biological aspects that are not represented by the Drosophila model, and in order to test to what degree gene functions are conserved within insects and what changes in gene function accompanied the evolution of novel traits, the establishment of respective tools in other insect species is required. While gene knock down can be induced by RNA interference in many insects, methods to misexpress genes are much less developed. In order to allow misexpression of genes in a timely controlled manner in the red flour beetle Tribolium castaneum, we have established a heat shock-mediated misexpression system. We show that endogenous heat shock elements perform better than artificial heat shock elements derived from vertebrates. We carefully determine the optimal conditions for heat shock and define a core promoter for use in future constructs. Finally, using this system, we study the effects of misexpressing the head patterning gene Tc-orthodenticle1 (Tc-otd1), We show that Tc-otd1 suppresses Tc-wingless (Tc-wg) in the trunk and to some degree in the head.Development Genes and Evolution 07/2012; 222(5):287-98. DOI:10.1007/s00427-012-0412-x · 2.18 Impact Factor
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- "Aphb and Apotd encode highly conserved domains that are common to Hb and Otd proteins in other insects (Figs. 1 and 2). Aphb and Apotd are expressed in the anterior region of embryos from stage 11 onward (Figs. 4 and 5), suggesting that both genes play a role in anterior patterning in A. pisum, as is the case in other insects Drosophila melanogaster (Finkelstein and Perrimon, 1990; Tautz et al., 1987), Tribolium castaneum (Schröder et al., 2008), and Nasonia vitripennis (Lynch et al., 2006; Pultz et al., 2005). Although Aphb and Apotd appear to play a role in anterior patterning, the details of their early expression patterns differ from those in other insects. "
ABSTRACT: In the dipteran Drosophila, the genes bicoid and hunchback work synergistically to pattern the anterior blastoderm during embryogenesis. bicoid, however, appears to be an innovation of the higher Diptera. Hence, in some non-dipteran insects, anterior specification instead relies on a synergistic interaction between maternally transcribed hunchback and orthodenticle. Here we describe how orthologues of hunchback and orthodenticle are expressed during oogenesis and embryogenesis in the parthenogenetic and viviparous form of the pea aphid, Acyrthosiphon pisum. A. pisum hunchback (Aphb) mRNA is localized to the anterior pole in developing oocytes and early embryos prior to blastoderm formation - a pattern strongly reminiscent of bicoid localization in Drosophila. A. pisum orthodenticle (Apotd), on the other hand, is not expressed prior to gastrulation, suggesting that it is the asymmetric localization of Aphb, rather than synergy between Aphb and Apotd, that regulates anterior specification in asexual pea aphids.Insect Molecular Biology 03/2010; 19 Suppl 2:75-85. DOI:10.1111/j.1365-2583.2009.00940.x · 2.98 Impact Factor
Genetics 01/2009; 180(4):1779-86. DOI:10.1534/genetics.104.98673 · 4.87 Impact Factor
- "Although a bicoid ortholog that originated as a Hox 3 duplication is recognizable in lower diptera (Stauber et al. 1999; Brown et al. 2001), as described below there is no such gene within the Tribolium Hox (Brown et al. 2001, 2002a; Richards et al. 2008). Additional studies of Tribolium and other insects support the role of orthodenticle as the ancestral anterior determinant (see Schroder et al. 2008). Tribolium studies have provided a series of insights into the evolution of Hox clusters. "