Gene expression/regulation definition

Loros We think there are some very subtle phenotypes in terms of fight-regulated gene expression. We are hoping definitive phenotypes may be easier to find in the WC knockout backgrounds. 

In most insects, pheromones are synthesized in specialized cells or tissues associated with the epidermis (Tillman et al., 1999). Biochemical analyses traced the localization of Scolytid pheromone accumulation to portions of the alimentary canal, particularly the hindgut (e.g. Borden et al., 1969 Byers, 1983), but the actual tissue source of pheromone components was unknown. Fortunately, the tight correlation of HMG-R gene expression with pheromone component biosynthesis meant that hybridization techniques could be used to map the location of pheromone biosynthesis. Northern blots provided the first maps, while in situ hybridizations definitively showed which tissues were elevating HMG-R mRNA in response to feeding or JH III treatment. As with endocrine regulation studies, the molecular and biochemical data complemented each other. 

Inferential evidence supports a role for nonhistone proteins in regulating eukaryotic gene expression (O Malley et al., 1977). The nonhistone proteins increase in amount in tissues carrying out RNA transcription, in the face of unchanged histone levels. The nonhistone proteins also exhibit a greater heterogeneity than the five histone proteins and possess DNA binding specificity. Nonetheless, a demonstration of an unequivocal role for these proteins will depend upon more definitive evidence than is presently available. 

However, clustering methods only identify genes that are highly correlated in their expression, not by their mechanism of regulation, which can only be definitely elucidated through empirical studies. 

---