The boundary paradox in the Bithorax complex

摘要: Abstract The parasegment-specific expression of the three Drosophila Bithorax complex homeotic genes is orchestrated by nine functionally autonomous regulatory domains. Functional autonomy depends upon special elements called boundaries or insulators that are located between each domain. ensure independent activity domain blocking adventitious interactions with initiators, enhancers and silencers in neighboring However, this poses a paradox — also able to insulate promoters from six domains separated their target at least one boundary element. Here we consider several mechanisms have been suggested for how bypass intervening direct appropriate temporal spatial gene.