Genome-wide screening of male accessory gland proteins and their hormonal regulation in the red flour beetle, Tribolium castaneum

Male accessory gland proteins (Acps) act as key modulators of reproductive success in insects by influencing the female reproductive physiology and behavior. Except for a few studies in Drosophila melanogaster and recently in other insects, the functional roles of Acps and their hormonal regulation remain unknown. Microarray analysis in the red flour beetle, Tribolium castaneum, identified 112 Acp genes that were highly expressed in male accessory glands (MAG) and code for a signal peptide cleavage sequence. Out of 112 Acps identified, 25 shared sequence homology and 47 shared functional homology with the Acps identified in other insect species. Quantitative real-time reverse transcriptase PCR analysis showed that the mRNA levels of JH-response genes (eg. Pepck) and genes involved in JH biosynthesis (JHAMT) increased in 0-120 h postecdysial adult virgin males. RNA interference (RNAi)-mediated knock-down in the expression of genes involved in JH biosynthesis (JHAMT) and JH action (Met) impaired the maturation and differentiation of MAGs as well as the expression of some of the putative Acps. These data suggest a critical role for JH in the regulation of male reproduction especially MAG secretions. Taken together, this study putforths the possibility of utilizing the male reproductive system to understand the functional roles of Acps, and the molecular mechanisms of JH actions in this model insect. Supported by NSF grant, IBN-0421856.