The Kruppel gap protein regulates the posterior boundary of eve stripe 2. The role of Kr gap protein in the formation of posterior border of eve stripe 2 can be explained in this way:
The posterior border formation of stripe 2 has the involvement of Bicoid activator and Kruppel repressor. The net output of this combination or the balance between the activators and repressors is expression of the narrow eve strip.
The minimal stripe element generates the posterior border of the stripe 2. It is formed by limiting levels of activators rather than repressors. A sharp limit of expression of genes is created by pattern element due to overlapping activator and repressor gradients.
The cis-acting regulating elements are regulated by combinations or balance between both activators and repressors. The spatial regulation of gene expression is done in this way.
To get simple outputs, a complex input pattern is integrated.