Direct interaction between Teashirt and Sex combs reduced proteins, via Tsh's acidic domain, is essential for specifying the identity of the prothorax in Drosophila

teashirt (tsh) encodes a zinc-finger protein that is thought to be part of a network that contributes to regionalization of the Drosophila embryo and establishes the domains of Hox protein function. tsh and the Hox gene Sex combs reduced (Scr) are essential to establish the identity of the first thoracic segment. We used the development of the first thoracic segment as a paradigm for Scr dependent regional morphological distinctions. In this specific context, we asked whether Tsh protein could have a direct influence on Scr activity. Here we present evidence that Tsh interacts directly with Scr and this interaction depends in part on the presence of a short domain located in the N-terminal half of Teashirt called "acidic domain". In vivo, expression of full length Tsh can rescue the tsh null phenotype throughout the trunk whereas Tsh lacking the Scr interacting domain rescues all the trunk defects except in the prothorax. We suggest this provides insights into the mechanism by which Tsh, in concert with Scr, specifies the prothoracic identity.     

Ornithodoros porcinus ticks, bushpigs, and African swine fever in Madagascar

African swine fever (ASF) has recently made its appearance in Madagascar. Ticks of the Ornithodoros moubata group, considered to be O. porcinus Walton, 1962 were formerly known to occur in western Madagascar, but seem to have disappeared from that region. However, three new sites where they occur were found in the humid and cool central highlands of Anatananarivo province. These ticks are known to be efficient reservoirs and vectors of ASF and constitute a considerable complication to the control of the disease. The authors also discuss another potentially complicating factor, the presence of a species of African bushpig, Potamochoerus larvatus.     

A critical role of teashirt for patterning the ventral epidermis is masked by ectopic expression of tiptop, a paralog of teashirt in Drosophila

The teashirt gene encodes a protein with three widely spaced zinc finger motifs that is crucial for specifying trunk identity in Drosophila embryos. Here, we describe a gene called tiptop, which encodes a protein highly similar to Teashirt. We have analyzed the expression patterns and functions of these two genes in the trunk of the embryo. Initially, teashirt and tiptop expressions are detected in distinct domains; teashirt in the trunk and tiptop in parts of the head and tail. In different mutant situations, we show that, in the trunk and head, they repress each other's expression. Unlike teashirt, we found that deletion of tiptop is homozygous viable and fertile. However, embryos lacking both gene activities display a more severe trunk phenotype than teashirt mutant embryos alone. Ectopic expression of either gene produces an almost identical phenotype, indicating that Teashirt and Tiptop have, on the whole, common activities. We conclude that Teashirt and Tiptop repress each other's expression and that Teashirt has a crucial role for trunk patterning that is in part masked by ectopic expression of Tiptop.     

Recombinant proteins L and LG

Several bacterial cell wall proteins, like proteins A and G, with valuable affinity for immunoglobulins have been discovered and are currently employed in immunological techniques. In 1988, protein L, a bacterial cell wall protein with Ig-binding capacity, was isolated from the anaerobic bacterial speciesPeptostreptococcus magnus. Binding data with immunoglobulin fragments suggested that protein L could selectively bind the variable region of human kappa light chains. More recently a recombinant LG fusion protein was expressed inE. coli containing four repeated Ig-binding domains of protein L (fragment B1–4) and two IgG Fc-binding protein G domains (fragment CDC). Recombinant L and LG proteins were tested in the purification of murine monoclonal IgG and their fragments. After affinity-constant evaluation in different buffer systems, high-pressure affinity-chromatography columns were prepared by coupling the proteins to Affi-prep 10 resin and tested with eight different murine monoclonal antibodies and their fragments of various isotypes. Affinity-chromatography experiments confirming radioimmunoassay results showed 75% fragment-binding capacity of protein L and 100% of protein LG. These results evidenced protein LG as the most powerful Ig-binding tool so far described. Therefore, application of these proteins may be suggested in the purification of murine immunoglobulins and their fragments, including the engineered ones.