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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

Sleep reduction in Nf1 mutants.A) Averaged sleep profiles of control iso31 (black) and Nf1P1/P2 (blue) mutant flies at 25°C. B) Average daily sleep for control iso31, Nf1 mutants and Nf1 flies with transgenic Nf1 gene rescue at 25°C. Comparisons were done with one-way ANOVA and post-hoc Turkey’s test. * indicates significant difference from iso31 control. Error bars are SEM. N = 5–16. Ns, not significant. ***p<0.001, ****p<0.0001. Nf1 transgenic expression in wild type background was done in a separate experiment and their sleep quantities were compared with the respective controls. C) Nf1 mutants exhibit nocturnal hyperactivity. Diurnal/nocturnal index was calculated as (total activity during the day) − (total activity during the night)/(total activity), averaged over a 3-d period per fly.
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pgen.1005611.g006: Sleep reduction in Nf1 mutants.A) Averaged sleep profiles of control iso31 (black) and Nf1P1/P2 (blue) mutant flies at 25°C. B) Average daily sleep for control iso31, Nf1 mutants and Nf1 flies with transgenic Nf1 gene rescue at 25°C. Comparisons were done with one-way ANOVA and post-hoc Turkey’s test. * indicates significant difference from iso31 control. Error bars are SEM. N = 5–16. Ns, not significant. ***p<0.001, ****p<0.0001. Nf1 transgenic expression in wild type background was done in a separate experiment and their sleep quantities were compared with the respective controls. C) Nf1 mutants exhibit nocturnal hyperactivity. Diurnal/nocturnal index was calculated as (total activity during the day) − (total activity during the night)/(total activity), averaged over a 3-d period per fly.

Mentions: Genetic interactions between Alk and Nf1 in growth and learning processes led us to investigate whether Nf1 is also required for sleep regulation. Interestingly, a prevalence of sleep disturbances has recently been reported in NF1 patients [44,]. We detected considerable variability in total sleep amount in Nf1 mutant flies across experiments. We tested three Nf1 alleles, Nf1P1, Nf1P2, and Nf1c00617. Nf1P1 and Nf1P2 alleles are both assumed to be because neither expresses NF1 protein and homozygous flies have similar defects in locomotor activity rhythms, body size and learning [22,46, 47]. Although the average total sleep of male flies harboring any two Nf1 alleles was significantly less than that of control flies, we did not observe a consistent difference between Nf1 mutant and control female flies (Fig 6). While Nf1P2/c00617 female flies slept less than controls, sleep amounts in Nf1P1/P2 female flies were generally not different from those of control flies. Furthermore, Nf1P1 and Nf1P2 female flies did not consistently show sleep reduction as compared to iso31 controls in separate experiments. Similar discrepancies were found when sleep was assayed with the multi-beam sleep monitors. However, both Nf1 male and female flies exhibited nocturnal hyperactivity (Fig 6A and 6C), which resulted in an increase in daytime sleep and a decrease in nighttime sleep. Nf1 mutants also showed consistent defects in sleep consolidation. Both daytime sleep and nighttime sleep were highly fragmented in Nf1 males, such that the average sleep bout duration was reduced and the number of sleep bouts increased (S8 Fig). While reductions in average bout duration did not reach significance in females, increased numbers of bouts suggest deficits in sleep maintenance and consolidation. Rescuing Nf1 with pan-neuronal expression of a UAS-Nf1 transgene increased sleep of Nf1 mutants and in fact caused a long sleep phenotype compared to wild-type controls. This did not result from ectopic expression of the transgene as expressing the same UAS-Nf1 transgene in wild-type flies had no effect (Fig 6B). Interestingly, sleep increase was seen with Nf1 rescue in both male and female flies, suggesting that effects of Nf1 on sleep are quite complex.


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

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

Sleep reduction in Nf1 mutants.A) Averaged sleep profiles of control iso31 (black) and Nf1P1/P2 (blue) mutant flies at 25°C. B) Average daily sleep for control iso31, Nf1 mutants and Nf1 flies with transgenic Nf1 gene rescue at 25°C. Comparisons were done with one-way ANOVA and post-hoc Turkey’s test. * indicates significant difference from iso31 control. Error bars are SEM. N = 5–16. Ns, not significant. ***p<0.001, ****p<0.0001. Nf1 transgenic expression in wild type background was done in a separate experiment and their sleep quantities were compared with the respective controls. C) Nf1 mutants exhibit nocturnal hyperactivity. Diurnal/nocturnal index was calculated as (total activity during the day) − (total activity during the night)/(total activity), averaged over a 3-d period per fly.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4633181&req=5

pgen.1005611.g006: Sleep reduction in Nf1 mutants.A) Averaged sleep profiles of control iso31 (black) and Nf1P1/P2 (blue) mutant flies at 25°C. B) Average daily sleep for control iso31, Nf1 mutants and Nf1 flies with transgenic Nf1 gene rescue at 25°C. Comparisons were done with one-way ANOVA and post-hoc Turkey’s test. * indicates significant difference from iso31 control. Error bars are SEM. N = 5–16. Ns, not significant. ***p<0.001, ****p<0.0001. Nf1 transgenic expression in wild type background was done in a separate experiment and their sleep quantities were compared with the respective controls. C) Nf1 mutants exhibit nocturnal hyperactivity. Diurnal/nocturnal index was calculated as (total activity during the day) − (total activity during the night)/(total activity), averaged over a 3-d period per fly.
Mentions: Genetic interactions between Alk and Nf1 in growth and learning processes led us to investigate whether Nf1 is also required for sleep regulation. Interestingly, a prevalence of sleep disturbances has recently been reported in NF1 patients [44,]. We detected considerable variability in total sleep amount in Nf1 mutant flies across experiments. We tested three Nf1 alleles, Nf1P1, Nf1P2, and Nf1c00617. Nf1P1 and Nf1P2 alleles are both assumed to be because neither expresses NF1 protein and homozygous flies have similar defects in locomotor activity rhythms, body size and learning [22,46, 47]. Although the average total sleep of male flies harboring any two Nf1 alleles was significantly less than that of control flies, we did not observe a consistent difference between Nf1 mutant and control female flies (Fig 6). While Nf1P2/c00617 female flies slept less than controls, sleep amounts in Nf1P1/P2 female flies were generally not different from those of control flies. Furthermore, Nf1P1 and Nf1P2 female flies did not consistently show sleep reduction as compared to iso31 controls in separate experiments. Similar discrepancies were found when sleep was assayed with the multi-beam sleep monitors. However, both Nf1 male and female flies exhibited nocturnal hyperactivity (Fig 6A and 6C), which resulted in an increase in daytime sleep and a decrease in nighttime sleep. Nf1 mutants also showed consistent defects in sleep consolidation. Both daytime sleep and nighttime sleep were highly fragmented in Nf1 males, such that the average sleep bout duration was reduced and the number of sleep bouts increased (S8 Fig). While reductions in average bout duration did not reach significance in females, increased numbers of bouts suggest deficits in sleep maintenance and consolidation. Rescuing Nf1 with pan-neuronal expression of a UAS-Nf1 transgene increased sleep of Nf1 mutants and in fact caused a long sleep phenotype compared to wild-type controls. This did not result from ectopic expression of the transgene as expressing the same UAS-Nf1 transgene in wild-type flies had no effect (Fig 6B). Interestingly, sleep increase was seen with Nf1 rescue in both male and female flies, suggesting that effects of Nf1 on sleep are quite complex.

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