Nutrition regulation of male accessory gland growth and maturation in Tribolium castaneum.

Jingjing Xu,Subba Reddy Palli,Ashlee L Anciro

doi:10.1038/srep10567

Abstract

Insulin/IGF-1 signaling (IIS) pathway is known to control growth, development and reproduction. Insulin-like peptide mediated body size plasticity in Drosophila melanogaster has been reported. Here, our studies showed that IIS pathway and nutrition regulate growth and maturation of the male accessory gland (MAG) in the red flour beetle, Tribolium castaneum. The size of MAG increased from day 1 to day 5 post-adult emergence (PAE). This increase in the size of MAG is contributed by an increase in cell size, but not cell number. The growth of MAG was impaired after double-stranded RNA (dsRNA)-mediated knockdown in the expression of genes coding for ILP3, InR, Chico, PI3k, AKT, and GATA1 involved in IIS pathway. Interestingly, starvation showed similar effects on the growth and maturation of MAG. The phenotypes observed in animals where IIS signaling pathway genes were knocked down are similar to the phenotypes observed after starving beetles for 5 days PAE. These data suggest that nutrition signals working through IIS pathway regulate maturation of MAG by promoting the growth of MAG cells.

Highlights

Affect male reproductive fitness as evidenced by a less vigor in mating behavior, poor sperm transfer, low egg and progeny production by females in both Tribolium castaneum and D. melanogaster[19,20]
We showed that nutrition and Insulin/IGF-1 (IIS) signaling pathway are required for vitellogenin gene expression in the red flour beetle, T. castaneum[21], suggesting IIS function in T. castaneum is very much conserved with that in D. melanogaster and mammals
Both starved and fed males were placed in the same incubator set at 40% humidity based on our previous report[23]

Summary

Introduction

Affect male reproductive fitness as evidenced by a less vigor in mating behavior, poor sperm transfer, low egg and progeny production by females in both Tribolium castaneum and D. melanogaster[19,20]. Endocrine factors play conserved roles in all the animals from insect to mammals to support a successful reproductive process. Little is known about how endocrine factors promote male reproduction during the MAG/prostate maturation. To study molecular mechanisms governing IIS regulation of male reproduction, T. castaneum has been employed as a model species. RNA interference, confocal imaging, protein amount measurement and sperm production estimation were served to determine how nutritional signals working through IIS regulate male reproduction

Methods

Results

Conclusion