Delayed behavioural aging and altered mortality in Drosophilaβ integrin mutants

Abstract

SummaryThe genetic basis for aging is being intensely investigated in a variety of model systems. Much of the focus in Drosophila has been on the molecular-genetic determinants of lifespan, whereas the molecular-genetic basis for age-related functional declines has been less vigorously explored. We evaluated behavioural aging and lifespan in flies harbouring loss-of-function mutations in myospheroid , the gene that encodes β β β β PS, a β β β β integrin. Integrins are adhesion molecules that regulate a number of cellular processes and developmental events. Their role in aging, however, has received limited attention. We report here that age-related declines in locomotor activity are ameliorated and that mean lifespan is increased in myospheroid mutants. The delayed functional senescence and altered mortality in myospheroid flies are independent of changes in body size, reproduction or stress resistance. Our data indicate that functional senescence and age-dependent mortality are influenced by β β β β integrins in Drosophila .

Genetic and environmental factors impact age-related impairment of negative geotaxis in Drosophila by altering age-dependent climbing speed

“…The studies reported here, in conjunction with previous work from our group (Goddeeris et al 2003;Gargano et al 2005) and others (Miquel et al 1976;Arking and Wells 1990;Chavous et al 2001;Mockett et al 2001;Kang et al 2002;Ruan et al 2002;Morrow et al 2004;Simon et al 2006), indicate that locomotor senescence might be mechanistically connected to life span in Drosophila; i.e. long-lived flies tend to have better locomotor function across age.…”

“…Negative geotaxis (startleinduced vertical movement) is a frequently used index of locomotor behavior in flies (Miquel et al 1976;Arking and Wells 1990;Chavous et al 2001;Mockett et al 2001;Kang et al 2002;Ruan et al 2002;Goddeeris et al 2003;Morrow et al 2004;Gargano et al 2005;Simon et al 2006).Despite being commonly assessed, it was previously unclear whether negative geotaxis is principally a climbing behavior or a combination of climbing and other behaviors such as jumping and flying. Additionally, it was previously unclear whether age-related impairment in negative geotaxis is due to a decreased speed of vertical movement, an increased latency to initiate vertical movement, or other age-related behavioral changes.…”

A proposed set of descriptors for functional senescence data

“…1A). The control data are derived from our previously published studies on senescence of negative geotaxis in wild-type flies (Goddeeris et al ., 2003). The divergent, convergent and parallel data sets are hypothetical; they were designed to represent three major types of actual results that might be consistent with ameliorated functional senescence as compared with the control (Fig.…”

“…The parallel group had elevated negative geotaxis scores at all ages so that its curve was parallel to control. Although statistical tests such as analysis of variance ( ANOVA ) can be used to compare overall function across age in data sets like these (e.g Goddeeris et al ., 2003), this approach leaves several questions unanswered, including: (1) Does the rate of functional decline differ between the data sets? (2) Is the time to onset of functional decline changed?…”

“…To illustrate how these descriptors can be used, we analyzed a hypothetical data set and one of our previously published data sets (Goddeeris et al ., 2003). We conclude that no one descriptor sufficiently characterizes functional senescence.…”