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Poster Full Abstracts - Physiology and Aging
Poster board number is above title. The first author is the presenter
330
The single available null mutation affects the common catalytic domain and is an embryonic lethal, thus hampering investigation of the function of these
products in adult tissues. The diversity of these functions have been investigated using tissue-specific GAL4 drivers and RNAi constructs. Ubiquitously
expressed GAL4 drivers (i.e.
tubP
GAL4) in combination with
Argk
RNAi results in lethality with the same lethal phase as the EMS-induced null. In
contrast, muscle-specific expression of GAL4 (i.e.
Mef2
GAL4) in combination with Argk RNAi bypasses the embryonic lethality and results in a flightless
phenotype and premature mortality supporting the importance of PD and PA products in flight muscle metabolism. GAL4 drivers restricted to germline
expression (i.e.
da
GAL4) in combination with
Argk
RNAi also bypasses the embryonic lethality, yet results in a unique female sterile phenotype in which
eggs fail to develop. These eggs are deficient in the PB product that is produced in nurse cells and transported to the egg suggesting this form is necessary
for early embryonic development. A testis-specific paralog of
Argk
, CG4546, results in a unique male sterile phenotype when eliminated by RNAi. In these
males the individualization process is blocked and functional, mature sperm are not produced.
744C
Genetic and imaging analyses of Drosophila sperm storage.
Xiangyi Lu, Benjamin Burger. Wayne State Univ, Detroit, MI.
The human polycystic kidney disease gene 2 (PKD2) encode a conserved calcium channel of the TRPP family. In variety of organisms studied, PKD2
channels localize and function on cilia and flagella, which are microtubule axoneme-containing, sensory and/or motile organelles of a common evolutionary
origin. PKD2 on renal epithelial cilia is mechano-sensitive and it generates calcium influx in response to fluid flows in the nephron. PKD2 mutations cause
PKD due to, presumably, a disruption of cilium-mediated fluid sensation. However, signaling events downstream of calcium entry are mostly unknown.
Drosophila Pkd2 localizes on the sperm flagella. Although Pkd2 null Drosophila are viable, the mutant males are largely sterile due to inability of the sperm
to move into sperm storage organs. Sperm storage or accumulation of sperm at a defined location of the female reproductive tract is a reproductive process
of many internally fertilizing species, including insects, birds and mammals. Movement of sperm into the storage site appears to be guided by external
signals, but not much is known. Using GFP imaging, we showed that Drosophila sperm are bidirectional swimmers. The sperm show complex motility
regulation in the reproductive tract, involving changes in both flagellar waveforms and wave directions. Pkd2 mutation affects the sperm’s tail-leading
movement for entering the sperm storage organs without affecting the head-leading movements for exiting the storage organ and for fertilizing the egg,
suggesting that Pkd2 regulates sperm movement via possibly sensory responses to sperm storage signals. Moreover, mutagenesis screens have led to five
new mutant loci that cause sperm storage phenotypes similar to that of Pkd2. One of these encodes Lobo, which is localized on the sperm flagellum and
appears to be an integral protein of the outer doublet microtubules. Genetic analyses indicate that Pkd2 and Lobo function in the same pathway. Other Pkd2-
like genes encode protein kinase, ATPase, and proteins of unknown functions - all are conserved from flies to humans. Our studies have shed a new light on
the Pkd2 pathway and sperm interaction with the female reproductive tract which drives speciation of insects.
745A
Female reproductive glands play essential roles in reproduction that may have been conserved during evolution.
Jianjun Sun, Allan Spradling.
Howard Hughes Medical Institute, Department of Embyology, Carnegie Institution for Science, Baltimore, MD. 21218.
Glands are associated with the female reproductive tract in diverse organisms. Yet the cellular and molecular pathways controlling their formation, and the
roles played by glandular secretions in sperm storage, capacitation, sperm-ova interactions, and early embryo implantation remain poorly known. We have
better characterized
Drosophila
spermathecal and parovarial development and used this knowledge to probe reproductive gland function. Three-cell
secretory units comprising a gland cell, a canal cell and an accessory cell generate the mature tissues, a process likely to be characteristic of diverse insect
glands. The transcription factor Lozenge specifies precursor cells within the genital disc while the nuclear hormone receptor Hr39 times and controls
subsequent gland formation. Notch signaling and its downstream target
hindsight
are essential for gland cell differentiation. Using genetic tools to
specifically alter gland cell formation, we demonstrate that secretions not only mediate sperm storage in both seminal receptacle and spermathecae, but also
control ovulation. Our work shows that
Drosophila
is a powerful model for analyzing conserved genes and mechanisms underlying sperm storage, sperm
capacitation, ovulation, and fertilization.
746B
dJun and Vri/dNFIL3 regulate age related cardiac senescence in Drosophila.
Herve TRICOIRE
1
, Veronique MONNIER
1
, Magali ICHE-TORRES
2
,
Michael RERA
1
, Vincent CONTREMOULINS
3
, Nathalie LALEVEE
2
, Laurent PERRIN
2
. 1) Unité de Biologie Fonctionnelle et Adaptative (BFA, Univ
Paris Diderot, Sorbonne Paris Cité, PARIS, France; 2) IBDML, UMR 6216 Campus de Luminy, 13288 Marseille Cedex 9 France; 3) Institut Jacques
Monod, CNRS-University Paris Diderot 75205 Paris cedex 13, France.
Cardiac aging is characterized by a progressive senescence of organ’s physiology, including a decrease of cardiac reserve, modifications of heart rate and
increased arrhythmias. To identify the molecular pathways involved in heart senescence, we identified biomarkers of aging by tissue specific transcriptome
comparison of young (10 days) versus aged (40 days) fly hearts. Data mining suggested specific pathways and regulatory inputs involved in heart aging. In
particular, the JNK/AP1 pathway but also the vri/dNFIL3 transcription factor were pointed, as well a potential role of oxidative stress (OS) in the process.
Tissue specific genetic manipulations were performed in the aging heart, and parameters of cardiac senescence were analyzed in vivo. Reducing or
increasing OS specifically in the cardiac tissue by manipulating Catalase activity respectively delayed or enhanced cardiac senescence. In addition, targeted
dJun and Vri knockdown both delay cardiac senescence, pointing to a central role of these transcription factors in heart aging.
747C
Identification and Characterization of Upstream Regulators of Nrf2 Signaling in
Drosophila melanogaster
.
Nirmalya Chatterjee
1
, Kerstin Spirohn
2
,
Michael Boutros
2
, Dirk Bohmann
1
. 1) Dept. of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY; 2) Division Signaling and
Functional Genomics, German Cancer Research Center, Heidelberg, Germany.
Oxidative stress causes widespread damage to macromolecules, cells and organisms. Accumulation of such damage over time is thought to drive the aging
process. Multiple signaling pathways respond to oxidative stress by regulating processes which limit or repair cell damage. The transcription factor Nrf2 is a
principal regulator of such antioxidant and stress defense mechanisms. Previous work by this and other labs indicates that Nrf2 also delays age associated
functional decline and influences longevity. Consistent with a role in aging, metabolic and longevity signals known to modulate longevity can regulate Nrf2