Change in size distribution of active polyribosomes associated with puff induction in Drosophila melanogaster salivary glands.
The polytene cells of Drosophila melanogaster larvae are ideally suited for the study of gene information flow during differentiation, in that gene derepression is visualized in the form of chromosomal modifications called puffs. One special group of temperature-sensitive puffs can be experimentally induced within 5 min after transfer of salivary glands from 24-37 degrees C. Glands at 37 degrees C also begin synthesizing several new polypeptides which are of higher molecular weight than the prominent polypeptides being synthesized in glands at 24 degrees C [1]. The present study demonstrates that there is also a shift toward the utilization of heavier or more rapidly sedimenting polyribosomes for protein synthesis in glands transferred from 24-37 degrees C. As a result of such studies it is reasonable to assume that the polyribosome redistribution after a heat shock results from the translation of larger mRNA molecules synthesized by the temperature-sensitive loci. Further studies are suggested to describe the role of heat-induced gene activity in maintaining homeostasis, as well as the manner by which such activity is induced, in cells subjected to dramatic temperature fluctuations.
D000818:Animals; D002454:Cell Differentiation; D002875:Chromosomes; D004331:Drosophila melanogaster / Q000648:ultrastructure; D066298:In Vitro Techniques; D011132:Polyribosomes / Q000648:ultrastructure*; D014176:Protein Biosynthesis; D012333:RNA, Messenger; D012469:Salivary Glands / Q000648:ultrastructure*; D013696:Temperature
D012333:RNA, Messenger