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Anaplastic Lymphoma Kinase Acts in the Drosophila Mushroom Body to Negatively Regulate Sleep.

Bai L, Sehgal A - PLoS Genet. (2015)

Bottom Line: We show that Alk mutants have increased sleep.We also report that mutations in Nf1 produce a sexually dimorphic short sleep phenotype, and suppress the long sleep phenotype of Alk.Thus Alk and Nf1 interact in both learning and sleep regulation, highlighting a common pathway in these two processes.

View Article: PubMed Central - PubMed

Affiliation: Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT
Though evidence is mounting that a major function of sleep is to maintain brain plasticity and consolidate memory, little is known about the molecular pathways by which learning and sleep processes intercept. Anaplastic lymphoma kinase (Alk), the gene encoding a tyrosine receptor kinase whose inadvertent activation is the cause of many cancers, is implicated in synapse formation and cognitive functions. In particular, Alk genetically interacts with Neurofibromatosis 1 (Nf1) to regulate growth and associative learning in flies. We show that Alk mutants have increased sleep. Using a targeted RNAi screen we localized the negative effects of Alk on sleep to the mushroom body, a structure important for both sleep and memory. We also report that mutations in Nf1 produce a sexually dimorphic short sleep phenotype, and suppress the long sleep phenotype of Alk. Thus Alk and Nf1 interact in both learning and sleep regulation, highlighting a common pathway in these two processes.

No MeSH data available.


Related in: MedlinePlus

Alk mutants have increased sleep.A) The restrictive temperature of 29°C reversibly increases sleep in Alkts/1 mutants. The averaged sleep profiles, plotted as average amounts of sleep in every 30-minute period, are shown for iso31 and Alkts/1 female flies. The white and the grey columns mark periods of day and night, respectively. N = 16. B) Quantification of average daily sleep of control flies and Alk mutants measured by single beam monitors. Total sleep at 18°C was calculated as the average of 3 days before the temperature shift to 29°C. Total sleep amounts at 29°C were calculated as the average of the 3 days following the temperature shift and are significantly different between genotypes (One-way ANOVA, p<0.0001). Asterisk* signifies difference from iso31 control. In this figure and all following figures, *, p<0.05; **,p<0.01; ****,p<0.0001; ns, not significantly different. Error bars are SEM. N = 13–16. C) Measurement by multi-beam monitors similarly revealed longer sleep in Alkts/1 flies at the restrictive temperature. There is no difference between genotypes at 18°C (p = 0.4722), while at 29°C Alkts/1 sleep significantly longer than iso31 and Alk1/+ flies. N = 15–16. D) Waking activity in the multi-beam monitors was measured at the restrictive temperature of 29°C and was defined as averaged number of beam crossings per minute during wake. N = 15–16. E) Normal negative geotaxis response in Alk mutants. The negative geotaxis response is measured as the percentage of flies climbing vertically >4 cm from the bottom of a vial within 10s of being tapped down. N = 5 (groups of 10 flies for each genotype).
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pgen.1005611.g001: Alk mutants have increased sleep.A) The restrictive temperature of 29°C reversibly increases sleep in Alkts/1 mutants. The averaged sleep profiles, plotted as average amounts of sleep in every 30-minute period, are shown for iso31 and Alkts/1 female flies. The white and the grey columns mark periods of day and night, respectively. N = 16. B) Quantification of average daily sleep of control flies and Alk mutants measured by single beam monitors. Total sleep at 18°C was calculated as the average of 3 days before the temperature shift to 29°C. Total sleep amounts at 29°C were calculated as the average of the 3 days following the temperature shift and are significantly different between genotypes (One-way ANOVA, p<0.0001). Asterisk* signifies difference from iso31 control. In this figure and all following figures, *, p<0.05; **,p<0.01; ****,p<0.0001; ns, not significantly different. Error bars are SEM. N = 13–16. C) Measurement by multi-beam monitors similarly revealed longer sleep in Alkts/1 flies at the restrictive temperature. There is no difference between genotypes at 18°C (p = 0.4722), while at 29°C Alkts/1 sleep significantly longer than iso31 and Alk1/+ flies. N = 15–16. D) Waking activity in the multi-beam monitors was measured at the restrictive temperature of 29°C and was defined as averaged number of beam crossings per minute during wake. N = 15–16. E) Normal negative geotaxis response in Alk mutants. The negative geotaxis response is measured as the percentage of flies climbing vertically >4 cm from the bottom of a vial within 10s of being tapped down. N = 5 (groups of 10 flies for each genotype).

Mentions: We assayed sleep using the traditional single infrared beam interruption device (Trikinetics, MA) in adult Alkts/1 and Alkts female flies at the permissive temperature of 18°C and at the restrictive temperature 29°C. Because genetic background has a profound impact on sleep [24], Alk mutants were backcrossed for five generations into a white (w) isogenic background, iso31, a line generated specifically for use in behavioral experiments [25]. At 18°C, control iso31 and Alk flies had very similar sleep patterns. However, acute inhibition of Alk by switching the environmental temperature to 29°C drastically increased sleep in Alk flies as compared to iso31. In iso31 flies, the shift to 29°C initially increased daytime sleep and decreased nighttime sleep, consistent with previous reports of increased siesta at higher temperatures [26]; overall sleep increased on the third day, but there was no net change in sleep over the three day period. Inhibition of Alk increased both day and night sleep. This temperature-sensitive sleep phenotype was reversed by lowering the temperature back to 18°C (Fig 1A). Quantification shows that Alkts/1 flies slept ~51.06±10.09% more than the control iso31 flies during the high temperature shift (6 independent experiments, n = 87 for iso31 and n = 80 for Alkts/1). Similarly, Alkts homozygous flies and flies that harbor an Alkts allele over a deficiency uncovering the Alk gene slept more than control flies at 29°C. There was no difference in total sleep amount between Alkts/1, Alkts, or Alkts/Def flies, suggesting that the restrictive temperature completely abolished ALKts protein function (Fig 1B). Importantly, we were able to rescue the sleep phenotype of Alk mutants by re-expressing Alk transgenically (discussed below).


Anaplastic Lymphoma Kinase Acts in the Drosophila Mushroom Body to Negatively Regulate Sleep.

Bai L, Sehgal A - PLoS Genet. (2015)

Alk mutants have increased sleep.A) The restrictive temperature of 29°C reversibly increases sleep in Alkts/1 mutants. The averaged sleep profiles, plotted as average amounts of sleep in every 30-minute period, are shown for iso31 and Alkts/1 female flies. The white and the grey columns mark periods of day and night, respectively. N = 16. B) Quantification of average daily sleep of control flies and Alk mutants measured by single beam monitors. Total sleep at 18°C was calculated as the average of 3 days before the temperature shift to 29°C. Total sleep amounts at 29°C were calculated as the average of the 3 days following the temperature shift and are significantly different between genotypes (One-way ANOVA, p<0.0001). Asterisk* signifies difference from iso31 control. In this figure and all following figures, *, p<0.05; **,p<0.01; ****,p<0.0001; ns, not significantly different. Error bars are SEM. N = 13–16. C) Measurement by multi-beam monitors similarly revealed longer sleep in Alkts/1 flies at the restrictive temperature. There is no difference between genotypes at 18°C (p = 0.4722), while at 29°C Alkts/1 sleep significantly longer than iso31 and Alk1/+ flies. N = 15–16. D) Waking activity in the multi-beam monitors was measured at the restrictive temperature of 29°C and was defined as averaged number of beam crossings per minute during wake. N = 15–16. E) Normal negative geotaxis response in Alk mutants. The negative geotaxis response is measured as the percentage of flies climbing vertically >4 cm from the bottom of a vial within 10s of being tapped down. N = 5 (groups of 10 flies for each genotype).
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pgen.1005611.g001: Alk mutants have increased sleep.A) The restrictive temperature of 29°C reversibly increases sleep in Alkts/1 mutants. The averaged sleep profiles, plotted as average amounts of sleep in every 30-minute period, are shown for iso31 and Alkts/1 female flies. The white and the grey columns mark periods of day and night, respectively. N = 16. B) Quantification of average daily sleep of control flies and Alk mutants measured by single beam monitors. Total sleep at 18°C was calculated as the average of 3 days before the temperature shift to 29°C. Total sleep amounts at 29°C were calculated as the average of the 3 days following the temperature shift and are significantly different between genotypes (One-way ANOVA, p<0.0001). Asterisk* signifies difference from iso31 control. In this figure and all following figures, *, p<0.05; **,p<0.01; ****,p<0.0001; ns, not significantly different. Error bars are SEM. N = 13–16. C) Measurement by multi-beam monitors similarly revealed longer sleep in Alkts/1 flies at the restrictive temperature. There is no difference between genotypes at 18°C (p = 0.4722), while at 29°C Alkts/1 sleep significantly longer than iso31 and Alk1/+ flies. N = 15–16. D) Waking activity in the multi-beam monitors was measured at the restrictive temperature of 29°C and was defined as averaged number of beam crossings per minute during wake. N = 15–16. E) Normal negative geotaxis response in Alk mutants. The negative geotaxis response is measured as the percentage of flies climbing vertically >4 cm from the bottom of a vial within 10s of being tapped down. N = 5 (groups of 10 flies for each genotype).
Mentions: We assayed sleep using the traditional single infrared beam interruption device (Trikinetics, MA) in adult Alkts/1 and Alkts female flies at the permissive temperature of 18°C and at the restrictive temperature 29°C. Because genetic background has a profound impact on sleep [24], Alk mutants were backcrossed for five generations into a white (w) isogenic background, iso31, a line generated specifically for use in behavioral experiments [25]. At 18°C, control iso31 and Alk flies had very similar sleep patterns. However, acute inhibition of Alk by switching the environmental temperature to 29°C drastically increased sleep in Alk flies as compared to iso31. In iso31 flies, the shift to 29°C initially increased daytime sleep and decreased nighttime sleep, consistent with previous reports of increased siesta at higher temperatures [26]; overall sleep increased on the third day, but there was no net change in sleep over the three day period. Inhibition of Alk increased both day and night sleep. This temperature-sensitive sleep phenotype was reversed by lowering the temperature back to 18°C (Fig 1A). Quantification shows that Alkts/1 flies slept ~51.06±10.09% more than the control iso31 flies during the high temperature shift (6 independent experiments, n = 87 for iso31 and n = 80 for Alkts/1). Similarly, Alkts homozygous flies and flies that harbor an Alkts allele over a deficiency uncovering the Alk gene slept more than control flies at 29°C. There was no difference in total sleep amount between Alkts/1, Alkts, or Alkts/Def flies, suggesting that the restrictive temperature completely abolished ALKts protein function (Fig 1B). Importantly, we were able to rescue the sleep phenotype of Alk mutants by re-expressing Alk transgenically (discussed below).

Bottom Line: We show that Alk mutants have increased sleep.We also report that mutations in Nf1 produce a sexually dimorphic short sleep phenotype, and suppress the long sleep phenotype of Alk.Thus Alk and Nf1 interact in both learning and sleep regulation, highlighting a common pathway in these two processes.

View Article: PubMed Central - PubMed

Affiliation: Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT
Though evidence is mounting that a major function of sleep is to maintain brain plasticity and consolidate memory, little is known about the molecular pathways by which learning and sleep processes intercept. Anaplastic lymphoma kinase (Alk), the gene encoding a tyrosine receptor kinase whose inadvertent activation is the cause of many cancers, is implicated in synapse formation and cognitive functions. In particular, Alk genetically interacts with Neurofibromatosis 1 (Nf1) to regulate growth and associative learning in flies. We show that Alk mutants have increased sleep. Using a targeted RNAi screen we localized the negative effects of Alk on sleep to the mushroom body, a structure important for both sleep and memory. We also report that mutations in Nf1 produce a sexually dimorphic short sleep phenotype, and suppress the long sleep phenotype of Alk. Thus Alk and Nf1 interact in both learning and sleep regulation, highlighting a common pathway in these two processes.

No MeSH data available.


Related in: MedlinePlus