Biology Reference
In-Depth Information
CHAPTER TWO
Nutrient Signaling
and Developmental Timing
of Maturation
Department of Biology, Cell and Neurobiology, University of Copenhagen, Copenhagen, Denmark
1
Corresponding author: e-mail address: Kim.Rewitz@bio.ku.dk
2
Equal contributions and order chosen randomly.
Contents
1.
Introduction
38
2.
Interplay Between Nutrients, Systemic Growth, and Developmental Transitions
41
2.1 Switching to a nutrient-independent developmental timing program
41
2.2 Insulin/target of rapamycin (TOR) couples nutrient-dependent growth
to timing of maturation
42
2.3 Influence of dietary amino acids, sugar, and fat on growth and onset
of maturation
44
3. A Nutritional Checkpoint Based on Crosstalk Between Different Tissues
48
3.1 Coordinating nutrient uptake and systemic growth
48
3.2 Interactions between the gut microbiota, nutrition, and developmental
progression
52
3.3 Crosstalk of nutrient signaling and neuroendocrine control of maturation
53
4. Fine-Tuning Systemic Insulin Signaling
54
4.1 Antagonistic interactions between ecdysone and insulin
54
4.2 Adjusting circulating DILP activity
55
5. A Developmental Checkpoint Couples Organ Growth and Tissue Regeneration
to Timing
57
6. Conclusions and Perspectives
60
Acknowledgments
61
References
61
Abstract
In animals, developmental timing of sexual maturation is tightly linked to nutrition and
growth. Maturation only occurs once the juvenile has acquired sufficient nutrients and
completed enough growth to produce a reproductively mature adult with a genetically
predefined body size. Animals therefore adjust the duration of juvenile development to
the dietary conditions. When nutrients are scarce the juvenile growth phase is extended
to compensate for slow growth. Conversely, development is accelerated in nutrient rich
environments where animals rapidly reach their genetic target size. To achieve such
