Sexual dimorphism in brain transcriptomes of Amami spiny rats (Tokudaia osimensis): a rodent species where males lack the Y chromosome

• Published in: BMC genomics Vol. 20; no. 1; p. 87
• Main Authors: Ortega, Madison T, Bivens, Nathan J, Jogahara, Takamichi, Kuroiwa, Asato, Givan, Scott A, Rosenfeld, Cheryl S
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 25.01.2019; BioMed Central; BMC
• Subjects: Animals; Brain; Brain - metabolism; Computational biology; Cysteine; Cystine; Cytochrome P-450; Dimorphism (Biology); DNA binding proteins; Endangered animals; Endangered species; Estrogens; Female; Gene Expression Profiling; Genes; Genetic aspects; Genetic research; Hormones; Male; Muridae; Murinae - genetics; Murinae - metabolism; Organizational-Activational programming; Phenols (Class of compounds); Physiological aspects; Proteins; Real-Time Polymerase Chain Reaction; RNA; RNA sequencing; Rodent; Rodents; Sequence Analysis, RNA; Serine; Sex Characteristics; Sexual differentiation; SRY; SRY genes; Steroid hormones; Testosterone; Transcriptome; Y Chromosome; Zinc finger proteins; Japan; Testosterone; Endangered animals; Estrogen; Organizational-Activational programming; SRY; Rodent; Bioinformatics; RNAseq; Sexual differentiation; Steroid hormones
• ISSN: 1471-2164; 1471-2164
• DOI: 10.1186/s12864-019-5426-6

Brain sexual differentiation is sculpted by precise coordination of steroid hormones during development. Programming of several brain regions in males depends upon aromatase conversion of testosterone to estrogen. However, it is not clear the direct contribution that Y chromosome associated genes, especially sex-determining region Y (Sry), might exert on brain sexual differentiation in therian mammals. Two species of spiny rats: Amami spiny rat (Tokudaia osimensis) and Tokunoshima spiny rat (T. tokunoshimensis) lack a Y chromosome/Sry, and these individuals possess an XO chromosome system in both sexes. Both Tokudaia species are highly endangered. To assess the neural transcriptome profile in male and female Amami spiny rats, RNA was isolated from brain samples of adult male and female spiny rats that had died accidentally and used for RNAseq analyses. RNAseq analyses confirmed that several genes and individual transcripts were differentially expressed between males and females. In males, seminal vesicle secretory protein 5 (Svs5) and cytochrome P450 1B1 (Cyp1b1) genes were significantly elevated compared to females, whereas serine (or cysteine) peptidase inhibitor, clade A, member 3 N (Serpina3n) was upregulated in females. Many individual transcripts elevated in males included those encoding for zinc finger proteins, e.g. zinc finger protein X-linked (Zfx). This method successfully identified several genes and transcripts that showed expression differences in the brain of adult male and female Amami spiny rat. The functional significance of these findings, especially differential expression of transcripts encoding zinc finger proteins, in this unusual rodent species remains to be determined.