摘要:

We describe the identification oflinotte, a new autosomal gene inDrosophilainvolved with learning and memory. Thelinotte' mutant was derived from aPlacWtransposon mutagenesis and was screened for three-hour memory deficits after classical conditioning of an olfactory avoidance response. Sensory and motor systems (olfactory acuity and shock reactivity) required for the classical conditioning experiments were normal in mutantlinotte1flies—indicating that the mutation disrupts learning/memory specifically. A chromosomal deficiency of the 37D region, where thelinotte1Pinsert was localizedin situ, failed to complementlinotte1's memory defect, and flies from two lines homozygous for independentPlacWexcisions show normal memory—indicating that thePinsertion is responsible for the mutant phenotype. Additional behavior-genetic data suggest thatlinottegene is non-vital.

ISSN:0167-7063    

DOI:10.3109/01677069309167272

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

The cAMP concentration inDrosophilais increased by mutations of thedunce(dnc) gene and decreased by mutations of therutabaga(rut) gene. Such mutants provide a unique means for exploring the role of cAMP in functional and developmental regulation of membrane currents. Four distinct K+currents have been identified inDrosophilalarval muscle fibers, i.e. the voltage-activated transient IAand delayed IKand the Ca2+-activated fast ICFand slow ICS. Results from our voltage-clamp studies indicated that both IAand IKwere increased indncalleles. Normal muscle fibers treated with dibutyryl-cAMP showed a similar increase of IA, but no significant effect on IK. In contrast to thedncalleles, therutmutations appeared to enhance ICSgreatly while leaving the amplitude of other currents largely unchanged. In addition, the dibutyryl-cAMP-induced increase in IAwas not observed inrutfibers. Caffeine and W7, which are known to interfere with several second messenger pathways, also modulted K+currents in larval muscle fibers. The currents indncandrutfibers showed strikingly altered responses to caffeine and W7. The results demonstrate that the various K+currents inDrosophilamuscles are affected by altered cAMP cascades in the mutants. The fact that not alldncandrutmutant defects can be mimicked or reversed by acute application of cAMP suggests that long-term modulation of K+currents by cAMP may involve mechanisms distinct from the short-term effect of cAMP.

ISSN:0167-7063    

DOI:10.3109/01677069309167273

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Previous work on thelozenge(lz) gene complex ofD. melanogasterhas focused on the compound eye. Here we study the effects of 22lzmutations on the antennal sensilla. The antenna of stronglzalleles is characterized by a lack of basiconic sensilla and by a significantly increased density of coeloconic sensilla. Intermediate alleles have few basiconic sensilla, they exhibit a highly increased density of trichoid sensilla, but a normal coeloconic density. Basiconic sensilla on the maxillary palps are weakly affected even by stronglzalleles. The antennal phenotype for most of the strong and intermediate mutants is partially dominant over wild type. Although this complicates the interpretation of complementation data, 12 selected mutants that were studied in heteroallelic combinations seem to define a single cistron. Temperature shifts of thelz1stallele showed that gene activity is crucial from about 87% of the third larval instar up to 7% of pupal life. Applying restrictive temperature early during this period results in a‘novel’phenotype that is characterized by a dramatic decrease in the density of trichoid sensilla, whereas a late pulse of restrictive temperature leads to a‘normal’intermediate phenotype. Our data suggest that thelzgene controls at least five different functions in the antenna: the size of the third antennal segment, the overall number and density of sensilla, the proportions of the 3 types of sensilla, and the generation of basiconic sensilla.

ISSN:0167-7063    

DOI:10.3109/01677069309167274

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

Initial learning, 30- and 180-min memory retention after Pavlovian conditioning of an odor avoidance response was quantified indnc1,dnc2,dncM11and Canton-S (wild-type) homozygotes and indnc1/FM7,dnc2/FM7,dncM11/FM7,dncM11/Can-S, Can-S/FM7,dnc1/dncM11anddnc2/dncM11heterozygotes. Our results consistently showed that a) theduncemutations are semi-dominant for initial learning and b) genetic variants carrying the enzymatically hypomorphicdnc2mutation produce learning scores lower than those of the amorphicdncM11. Analysis of this particular set of retention intervals, using a modified statistical model designed to evaluate decay rates, revealed no discernable effects of theduncemutations on memory formation 30 to 180 min after training. These results are consistent with a model of memory formation, in whichdunceis hypothesized to disrupt acquisition and/or short-term memory.

ISSN:0167-7063    

DOI:10.3109/01677069309167275

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor