The Tsx gene resides at the X-inactivation center and is thought to encode a protein expressed in testis, but its function has remained mysterious. Given its proximity to noncoding genes that regulate X-inactivation, here we characterize Tsx and determine its function in mice. We find that Tsx is actually noncoding and the long transcript is expressed robustly in meiotic germ cells, embryonic stem cells, and brain. Targeted deletion of Tsx generates viable offspring and X-inactivation is only mildly affected in embryonic stem cells. However, mutant embryonic stem cells are severely growth-retarded, differentiate poorly, and show elevated cell death. Furthermore, male mice have smaller testes resulting from pachytene-specific apoptosis and a maternal-specific effect results in slightly smaller litters. Intriguingly, male mice lacking Tsx are less fearful and have measurably enhanced hippocampal short-term memory. Combined, our study indicates that Tsx performs general functions in multiple cell types and links the noncoding locus to stem and germ cell development, learning, and behavior in mammals.
Early brain development can be influenced by numerous genetic and environmental factors, with long-lasting effects on brain function and behavior. Identification of these factors is facilitated by high-throughput analyses of behavior in zebrafish larvae, which can be imaged in multiwell or multilane plates. However, the nutritional needs of zebrafish larvae during the behavioral experiments are not fully understood. Zebrafish larvae begin feeding between 4 and 5 days postfertilization (dpf), but can live solely on nutrients derived from the yolk until at least 7 dpf. To examine whether feeding affects behavior, we measured a broad range of behaviors with and without feeding at 5, 6, and 7 dpf. We found that feeding did not have a significant effect on behavior in 5-day-old larvae. In contrast, fed 6- and 7-day-old larvae displayed increased avoidance responses to visual stimuli, increased swim speeds, and decreased resting in comparison to unfed larvae. In addition, the fed 7-day-old larvae displayed a decrease in thigmotaxis and a decrease in the distance between larvae in the presence of visual stimuli. Thus, feeding affects a range of behaviors in 6- and 7-day-old larvae. We conclude that 5-day-old larvae are well-suited for high-throughput analyses of behavior, since effects of feeding can be avoided at this time. For high-throughput analyses of behavior in older larvae, standard feeding protocols need to be developed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.