DNA methylation and expression of the egfr gene are associated with worker size in monomorphic ants

Abstract

The reproductive division of labour is a hallmark of eusocial Hymenoptera. Females are either reproductive queens or non-reproductive workers. In ants, workers often display further task specialisation that is associated with variation in size and/or morphology. Because female polyphenism is typically under environmental control, it is thought epigenetic mechanisms (such as DNA methylation) play a central role since they mediate gene-by-environment interactions. Methylation of the growth-promoting gene epidermal growth factor receptor (egfr) was indeed shown to control worker size in a highly polymorphic ant. However, it remains unknown if egfr methylation could also regulate worker size in monomorphic species. By combining experimental pharmacology and molecular biology, we show that worker size is associated with egfr methylation in two monomorphic ants. Furthermore, we functionally demonstrate that EGFR signalling affects worker size. These results indicate that worker size regulation by egfr methylation has been mechanistically conserved in ants but remains unexploited in monomorphic species.

Sex- and caste-specific developmental responses to juvenile hormone in an ant with maternal caste determination

“…How caste-specific queen and worker body sizes are attained is not well understood, but studies focusing on size variation within the worker caste have brought valuable insight. Methylation of epidermal growth factor receptor , which links to JH via the insulin signalling pathway, appears to play a key role in determining worker size, both in species with distinct worker castes (Alvarado et al ., 2015) and in species with monomorphic workers (Renard et al ., 2022). JH itself has been implicated in increased body size of Pheidole soldiers (Wheeler & Nijhout, 1981, 1983; Rajakumar et al ., 2012) and Pogonomyrmex and Camponotus workers (Cahan et al ., 2011; LeBoeuf et al ., 2016).…”

“…with task in bee workers (Whitfield et al ., 2003; Grozinger & Robinson, 2007; Shpigler et al ., 2010; Johnson & Jasper, 2016), and with caste (Glastad et al ., 2021; Zhang et al ., 2021) and reproductive status in ants (Araki et al ., 2020; Gospocic et al ., 2021). During worker development, pharmacologically-induced hypomethylation resulting in increased expression of the growth-promoting egfr gene was associated with decreased kr-h1 expression, and an increase in body size (Renard et al ., 2022). Similarly, knockout of an estrogen-related receptor resulted in decreased kr-h1 expression (Zhang et al ., 2021).…”

Royal Jelly: Biological Action and Health Benefits

“…The most important bioactive components of RJ and their functional roles are shown in Table 2. proliferation of intestinal epithelial cells (IEC-6), [31] increase in lifespan in invertebrates, [11,26,53] proliferation rat hepatocytes, [26] larvae differentiation into queen via epidermal growth factor signaling, [11,30,43,44,47,48] self-renewal of stem cells, [11,26,30] proliferation of human monocytes and Jurkat lymphoid cell [33,35,44] MRPJ2 and isoform (Alternative name: Apalbumin 2)…”

“…The effects of royalactin on body size are mediated by p70 S6 kinase, the increased activity of mitogen-activated protein kinase (MAPK), and a shortened developmental time, whereas an increased concentration of the juvenile hormone affects the development of ovaries. All these effects during the bee larvae differentiation into queens are triggered through the activation of the epidermal growth factor receptor (EGFR) signaling pathway [ 30 , 43 , 44 ].…”

“…In human cell cultures, lipid components of RJ inhibited the aging process through the upregulation of EGF signaling and downregulation of insulin-like growth factors (IGF) [ 5 , 109 , 110 , 111 ]. In mouse embryonic stem cells, it was shown that royalactin can maintain pluripotency by activating a ground-state pluripotency-like gene network [ 44 ]. Furthermore, the same authors discovered Regina, a mammalian structural analog of royalactin that can promote ground-state pluripotency in mouse embryonic stem cells, indicating the possibility of using royalactin as a regenerative therapy.…”