High impact information on tsh

• Sequencing of a tsh cDNA shows that the putative protein possesses three distantly spaced CX2CX12HX5H zinc finger motifs [1].
• In situ hybridization of a tsh probe to embryos shows that this gene is expressed in a way similar to the reporter gene [1].
• Finally, brinker and tsh produce similar mutant phenotypes in the ventral epidermis, and double mutants mimic overactive Wg signaling in this tissue [2].
• Teashirt is required for transcriptional repression mediated by high Wingless levels [3].
• Teashirt is also a repressor of the homeotic gene labial in this tissue [3].

Biological context of tsh

• teashirt (tsh) encodes a Drosophila zinc-finger protein [4].
• By responding to signals as well as localized transcription regulators, the tsh transcription factor is produced in a spatial pattern distinct from any of the homeotic genes [5].
• Instead, the maintenance of tsh repression requires Polycomb group (PcG) mediated gene silencing, which is dispensable for hth repression [6].
• Role of the teashirt gene in Drosophila midgut morphogenesis: secreted proteins mediate the action of homeotic genes [5].
• Here we show that Wingless signalling promotes the phosphorylation and the nuclear accumulation of Teashirt [7].
• In the developing eye disc, Tsh and Homothorax (Hth) cooperatively induces the expression of microRNA bantam, which promotes progenitor cell growth and prevents apoptosis. This tissue-specific DNA-binding event by Tsh+Hth mediates the function of co-activator Yorkie (Yki) and the Hippo signaling pathway. [8]

Anatomical context of tsh

• Antp activates tsh in anterior midgut mesoderm [5].
• One is to promote sclerite development in the head region, in parallel with Hox genes; the other is to cooperate with Antennapedia and teashirt to suppress head-like sclerite development in the thorax [9].
• Whereas clones of cells expressing the teashirt transgene survive in the endogenous Teashirt domain, most cells expressing Teashirt in an ectopic distal position are lost from the epithelium [10].

Associations of tsh with chemical compounds

• Finally, we present evidence that the serine/threonine kinase Shaggy is associated with Teashirt in a complex [7].

Physical interactions of tsh

• One Armadillo-binding protein in Drosophila is the zinc finger protein Teashirt [7].

Regulatory relationships of tsh

• Tsh is ectopically induced at the border of Tollo-expressing clones [11].
• Under mild heat-shock conditions, the Teashirt protein induces an almost complete transformation of the labial to prothoracic segmental identity, when expressed before 8 hours of development [12].
• Second, Grunge acts positively to regulate teashirt expression in proximoventral parts of the leg [13].

Other interactions of tsh

• Setting limits on homeotic gene function: restraint of Sex combs reduced activity by teashirt and other homeotic genes [14].
• Thus, repression of Tsh defines the presumptive wing earlier in development than repression of Hth, which must therefore be considered a secondary event [15].
• We also show that in tsh mutants, disco is expressed in the trunk segments, probably explaining the partial trunk to head transformation reported in these mutants, but more importantly demonstrating interactions between members of this regionalization network [16].
• This process requires the binding of Teashirt to the C-terminal end of Armadillo [7].
• Furthermore, teashirt and eyeless induce the expression of each other, suggesting that teashirt is part of the gene network that functions to specify eye identity [17].

References