Searching for Major Urinary Proteins (MUPs) as Chemosignals in Urine of Subterranean Rodents

Abstract

Chemosensory information mediates behavior in many rodent genera. Major Urinary Proteins (MUPs) facilitate chemical communication in some species of mice. We sought to demonstrate the importance of MUPs in chemosignaling across a range of rodent genera that live in different habitats and social structures. We analyzed urine from three subterranean rodent genera from different continents, and with diverse social systems: eusocial Zambian mole-rats (Fukomys), solitary Israeli blind mole rats (Spalax), and social Chilean coruros (Spalacopus). 2D gel electrophoresis revealed low levels of protein, with sequences similar to aphrodisin, in Fukomys mole-rat urine, but no MUPs in urine of any of the studied species. Previous research demonstrated that subjects from the tested genera responded differentially to odors indicating transmission of individuality, family/colony or population, species, and reproductive state in secretions and excretions of conspecifics. This extends, to subterranean rodents, the evidence that rodent species can successfully transmit and receive chemosignals without the necessity of MUPs.

Mouse Lipocalins (MUP, OBP, LCN) Are Co-expressed in Tissues Involved in Chemical Communication

“…Furthermore, many species do not have multiple copies of Mup genes and thus MUP products-a major component of chemical signaling and olfaction in mice and rats-but express functional OBPs. This has been shown in many mammals (Singer and Macrides, 1990;Stopkova et al, 2010;Hagemeyer et al, 2011;Nagnan-Le Meillour et al, 2014) and it is our hope that potentially diverse functionsi.e., including the detoxification roles (Stopková et al, 2009;Kwak et al, 2011Kwak et al, , 2016)-of these proteins will be further resolved.…”

“…Obp genes have also undergone a series of duplications in mice, and they occur in a cluster of six genes and two pseudogenes on the X chromosome (Stopková et al, 2009(Stopková et al, , 2014 Figure 1A). Whilst the Mup genes are abundant only in house mice and rats (Rattus norvegicus) and rarely found in other species of mammals in multiple copies, Obp genes occur as a cluster in various mammalian taxa, e.g., porcupines (Hystrix cristata) (Felicioli et al, 1993), bank voles (Myodes glareolus) (Stopkova et al, 2010), elephants (Lazar et al, 2002), cows (Bos taurus) (Bignetti et al, 1985), boar (Sus scrofa) (Spinelli et al, 1998;Nagnan-Le Meillour et al, 2014), and potentially also mole rats (Fukomys anselli, F. kafuensis) (Hagemeyer et al, 2011). One OBP member (i.e., Aphrodisin) has been shown to be major pheromone transporter in vaginal flushes of hamsters (Cricetus cricetus).…”

Complementary roles of mouse lipocalins in chemical communication and immunity

“…In species where OBPs are produced in the liver and passaged out by the kidneys via urine, OBPs might have taken the communication roles described for MUPs that are absent from many species. These would, for example, include bank voles [46], and underground-dwelling mole rats [47]. Furthermore, humans have lost the genes for MUPs as well as the genes for true X-linked OBPs.…”

Evolutionary patterns of major urinary protein scent signals in house mice and relatives

“…The MUP signatures in wild mouse populations ( M. m. domesticus ) provide important social information on individual identity and sex. Previous analyses of mammalian genomes and rodent urine have shown that the patterns of MUP production seen in house mice are not widespread among rodents (Beynon et al, ; Hagemeyer et al, ; Logan et al, ). This raises interesting questions about the evolutionary origins of information content in mouse MUP signatures.…”