Social dominance‐related major urinary proteins and the regulatory mechanism in mice

Abstract

Major urinary proteins (MUPs) have been proven to be non-volatile male pheromones in mice. Here, we aimed to elucidate the relationship between MUPs and dominance hierarchy, and the underlying molecular mechanisms. Dominance-submission relationship was established by chronic dyadic encountering. We found that at the urinary protein level and hepatic mRNA level, the expression of major MUPs, including Mup20, was enhanced in dominant males compared with subordinate males, indicating that MUPs might signal the social status of male mice. Meanwhile, the mRNA level of hepatic corticotropin releasing hormone receptor 2 (CRHR2) was higher in subordinate male mice than in dominant male mice. Castration also enhanced the expression of CRHR2, but suppressed that of MUPs. CRHR2 agonist treatment reduced the expression of MUPs in liver. However, male social status failed to exert significant influence on serum testosterone and corticosterone as well as the mRNA expression of their receptors. These findings reveal that some MUPs, especially Mup20, might constitute potential dominance pheromones and could be downregulated by hepatic CRHR2, which is possibly independent of androgen or corticosterone systems.

Diversity of major urinary proteins (MUPs) in wild house mice

“…However, further analyses are needed to confirm protein identification, evaluate variation and consistency across all Mup loci, and over a longer time and across different conditions. MUP production is dynamically regulated with changes in age27, health2829, diet30, and social status3132, and we recently found that MUP proteins are differentially regulated when males are placed in competitive social conditions33. Thus, MUP expression profiles are phenotypically plastic, rather than constitutive (developmentally fixed), and studies are needed to investigate how variation and consistency in MUP expression influences individual odor , especially under more natural conditions.…”

Temporal dynamics of social hierarchy formation and maintenance in male mice

“…Compared to subordinate animals, dominant males have higher levels of major urinary proteins (MUPs) that bind to signalling volatile compounds (e.g. 2-secbutyl-4,5-dihydrothiazole and 3,4-dehydro-exo-brevicomin) (Apps, Rasa, & Viljoen, 1988;Guo, Fang, Huo, Zhang, & Zhang, 2015;Harvey, Jemiolo, & Novotny, 1989;Humphries, Robertson, Beynon, & Hurst, 1999;Kaur et al, 2014;Nelson et al, 2015;Stowers & Kuo, 2015). Some of these urinary proteins (e.g.…”

Regulation of highly homologous major urinary proteins in house mice quantified with label-free proteomic methods

“…Social interactions in the laboratory have been found to affect the regulation of urinary MUPs. 8,11 However, studies are needed to determine whether MUP production is socially regulated in more natural conditions (ecological validation). There are increasing studies showing changes in gene expression due to individual versus group housing.…”