Previous studies have shown that ubiquitous expression of gooseberry ectopically activates the endogenous gsb gene in cells located anterior to the wild-type stripe. Heat shock gsb is also able to activate the formation of an ectopic strip of lbe . As for gsb , this phenomenon is wg -dependent and cannot be detected in wg mutants. In the dorsal epidermis, both wg and lbe are gsb -independent.
Ladybird is a component of a cardiogenic pathway required for diversification of heart precursors.
Expression of lb genes in the subset of cardioblast and pericardial cell precursors is critically dependent on mesodermal tinman function, epidermal Wingless signaling and the coordinate action of neurogenic genes . Negative regulation by hedgehog is required to restrict ladybird expression to two out of six cardioblasts in each hemisegment. Surprisingly, the number of eve -expressing pericardial cells is strongly reduced in overexpressors. These lb expressing cells are transformed into l -paracardial cells. Loss of ladybird function leads to the opposite transformation, suggesting that ladybird participates in the determination of heart lineages and is required to specify the identities of subpopulations of heart cells.