1.C.105 The Bacillus thuringiensis Vegetative Insecticidal Protein-3 (Vip3) Family
Bacillus thuringiensis is an entomopathogenic bacterium producing parasporal proteinaceous insecticidal crystal inclusions during sporulation. Many strains are capable of also expressing other insecticidal proteins called Vip during the vegetative growing phase. Vip3A proteins have activity against certain Lepidoptera species through a unique mechanism of action which emphasized their possible use in resistance management strategies against resistant pests. Thirteen vip3Aa genes were identified in strains belonging to 10 different B. thuringiensis serovars. Three intra-subclass variants of vip3Aa genes could be differentiated (Sauka et al. 2012). This is the first report where variants of a single subclass of insecticidal genes were distinguished following PCR-RFLP.
The entomopathogenic bacterium, B. thuringiensis, produces parasporal crystalline inclusions during sporulation containing insecticidal proteins such as Cry and Cyt proteins [Sauka and Benintende, 2008], but many strains also produce other kinds of insecticidal proteins during the vegetative growing phase that do not form crystals and these are called Vip (vegetative insecticidal proteins) [Estruch et al., 1996]. This type of proteins include Vip1, Vip2 and Vip3. Vip1 (TC#1.C.42) and Vip2 are the components of binary toxins that have coleopteran specificity, whereas Vip3 proteins have activity against a wide variety of lepidopteran pests [Estruch et al., 1996; Warren, 1997]. To date, these three groups of Vip proteins can also be classified into 9 subgroups, 27 classes and 92 subclasses according to their amino acid sequence similarity (http://www.lifesci.sussex.ac.uk/home/Neil_Crickmore/Bt/vip.html).
Among these proteins, Vip3A do not share homology with other known proteins and act against lepidopteran larvae through a unique mechanism of action [Bhalla et al., 2005; Estruch et al., 1996; Lee et al. 2003, 2006]. These proteins act by binding to specific receptors, different when compared to that of Cry, located in the midgut epithelium of susceptible insect species. Then, cation-specific pores are formed that disrupt ion flow in the midgut, causing paralysis and death [Lee et al., 2006].
The vegetative insecticidal protein, Vip3Aa (789 aas) (Sauka et al. 2012)
Vip3Aa of Bacillus thuringiensis (F6GPK9)
The vegetative insecticidal protein Vip3Ca2 (803 aas) (Sauka et al. 2012).
Vip3Ca2 of Bacillus thuringiensis (G9DCX5)
Uncharacterized protein of 1179 aas.
Cellvibrionaceae bacterium AOL6
The 235 kDa rhoptry protein (1081 aas) (Proellocks et al. 2010)
Rhoptry protein of Plasmodium yoelii (Q7RFQ7)
Reticulocyte binding protein of 2968 aas, a homologue of PSAC throughout half of its length.
Reticulocyte binding protein of Plasmodium falciparum
Uncharacterized protein of 1212 aas
UP of Mycoplasma anatis
Uncharacterized protein of 875 aas
UP of of Cellulophaga algicola
Uncharacterized protein of 710 aa
UP of Naumovozyma dairenensis (Saccharomyces dairenensis)
Uncharacterized protein of 1810 aas
UP of Plasmodium gallinaceum
Uncharacterized protein of 1295 aas, similar to AMEV15.
UP of Choristoneura rosaceana entomopoxvirus L
Viral A-type inclusion protein (2011 aas). This protein includes a large hydrophilic domain that is homologous to regions in the dystrophins (TC# 8.A.66) the nucleoporin, 1.I.1.1.1, Q02455, the TypeIV protein secretion system, 3.A.7.12.1, O25262, and the KX family protein, 2.A.112.3.2, G0ZX98.
Inclusion protein of Trichomonas vaginalis (A2ETW9)
Uncharacterized protein of 973 aas. This protein is also homologous to the nucleoprin, 1.I.1.1.1; Q02455 and the TypeIV protein secretion system, 3.A.7.12.1; O25262.
UP of Paramecium tetraurelia
Uncharacterized protein of 642 aas
UP of Tetrahymena thermophila
Uncharacterized protein of 1418 aas
UP of Paramecium tetraurelia
Fibronectin binding autolysin/adhesin of 1395 aas, AtlC.
AtlC of Staphylococcus caprae
Surface protein with adhesive and autolytic activity of 1463 aas, Aas (Hell et al. 1998).
Aas of Staphylococcus sparophyticus
Uncharacterized protein of 529 aas.
UP of Ruminococcus torques
MCU homologue (872 aas; 2 TMSs)
MCU homologue of Halanaerobium praevalens (E3DLQ2)