Behaviour modification by in vitro mutagenesis of a variable region within the period gene of Drosophila

The period gene of Drosophila melanogaster, implicated in the control of both the circadian and male courtship song rhythms, is found to be polymorphic. Alleles differ in the length of a region of the gene encoding a series of threonine-glycine repeat units. The phenotypes of transformed fruit flies, in which the only functional period gene lacks the entire perfect threonine-glycine repeat region, show that the effects of the period gene on the circadian and male courtship song rhythms can be dissociated.     

Laboratory and field studies of the female sex pheromone of the olive moth,Prays oleae

Summary Analysis by GC-EAG indicates that abdominal tip extracts of femalePrays oleae contain a tetradecenal. Synthetic (Z)-7-tetradecenal elicits a strong EAG respones from maleP. oleae and field tests it to be comparable in attractancy with the virgin female moth. (Z)-9-Tetradecenal also produces a strong EAG response but it is not an attractant and, when added to (Z)-7-tetradecenal, markedly reduces trap catches.Acknowledgments. The authors are indebted to Mr N. Psylakis, Agricultural Research Centre, Chania, Crete, and to Dr D. Vassilopoulos, Benaki Phytopathological Institute, for providing facilities for this work. They thank the Commonwealth Institute of Entomology, London, for moth species confirmation.     

Normal p21N-ras couples bombesin and other growth factor receptors to inositol phosphate production

Many receptors, in response to ligand activation, trigger inositol phospholipid breakdown, which leads to rapid intracellular responses. The sustained activation of this pathway is believed to be at least one of the factors involved in the stimulation of cell growth and there has been much speculation that certain oncogenes use this pathway to effect uncontrolled cellular proliferation. It has been suggested, by analogy with the receptor-mediated control of adenylate cyclase, that the receptor stimulation of inositol phospholipid metabolism is mediated through a guanine nucleotide regulatory protein (G-protein) called Gp (or Np). Although such a species has not been identified, there is now strong experimental evidence that this process is mediated by a G-protein distinct from the stimulatory and inhibitory G-proteins (Gs and Gi, respectively). The ras genes code for a plasma membrane protein, p21, whose only known biochemical property is a high-affinity GTPase activity. We show here that the expression of normal p21N-ras in NIH 3T3 fibroblasts leads to the coupling of certain growth factor receptors to stimulated inositol phosphate production. We propose that the N-ras proto-oncogene encodes a protein which couples the receptors for certain growth factors to the stimulation of phospholipase C. Thus, N-ras p21 may be the putative Gp or a functionally related protein.     

Activation of the NADPH oxidase involves the small GTP-binding protein p21rac1

Professional phagocytes, such as neutrophils and monocytes, have an NADPH oxidase that generates superoxide and other reduced oxygen species important in killing microorganisms. Several components of the oxidase complex have been identified as targets of genetic defects causing chronic granulomatous disease. The complex consists of an electron transport chain that has as its substrate cytosolic NADPH and which discharges superoxide into the cavity of the intracellular phagocytic vacuole. The only electron transport component identified so far is a low-potential cytochrome b, apparently the only membrane component required. At least three cytosolic factors are also necessary, two of which, p67phOx and p47phOx, have been identified by their absence in patients with chronic granulomatous disease. A third component, sigma 1, is required for stimulation of oxidase activity in a cell-free system. The active components of purified sigma 1 are two proteins that associate as heterodimers, and here we report that these are the small GTP-binding protein p21rac1 and the GDP-dissociation inhibitor rhoGDI.