Sexually dimorphic expression of the sex chromosome-linked genes cntfa and pdlim3a in the medaka brain.
In vertebrates, sex differences in the brain have been attributed to differences in gonadal hormone secretion; however, recent evidence in mammals and birds shows that sex chromosome-linked genes, independent of gonadal hormones, also mediate sex differences in the brain. In this study, we searched for genes that were differentially expressed between the sexes in the brain of a teleost fish, medaka (Oryzias latipes), and identified two sex chromosome genes with male-biased expression, cntfa (encoding ciliary neurotrophic factor a) and pdlim3a (encoding PDZ and LIM domain 3 a). These genes were found to be located 3-4 Mb from and on opposite sides of the Y chromosome-specific region containing the sex-determining gene (the medaka X and Y chromosomes are genetically identical, differing only in this region). The male-biased expression of both genes was evident prior to the onset of sexual maturity. Sex-reversed XY females, as well as wild-type XY males, had more pronounced expression of these genes than XX males and XX females, indicating that the Y allele confers higher expression than the X allele for both genes. In addition, their expression was affected to some extent by sex steroid hormones, thereby possibly serving as focal points of the crosstalk between the genetic and hormonal pathways underlying brain sex differences. Given that sex chromosomes of lower vertebrates, including teleost fish, have evolved independently in different genera or species, sex chromosome genes with sexually dimorphic expression in the brain may contribute to genus- or species-specific sex differences in a variety of traits.
['Maehiro|Sayaka|S|', 'Takeuchi|Akio|A|', 'Yamashita|Junpei|J|', 'Hiraki|Towako|T|', 'Kawabata|Yukika|Y|', 'Nakasone|Kiyoshi|K|', 'Hosono|Kohei|K|', 'Usami|Takeshi|T|', 'Paul-Prasanth|Bindhu|B|', 'Nagahama|Yoshitaka|Y|', 'Oka|Yoshitaka|Y|', 'Okubo|Kataaki|K|']
D000595:Amino Acid Sequence D000818:Animals D001921:Brain D020934:Ciliary Neurotrophic Factor D004958:Estradiol D005260:Female D029941:Fish Proteins D015870:Gene Expression D020869:Gene Expression Profiling D008040:Genetic Linkage D008297:Male D008969:Molecular Sequence Data D020411:Oligonucleotide Array Sequence Analysis D009990:Oryzias D010802:Phylogeny D020133:Reverse Transcriptase Polymerase Chain Reaction D017386:Sequence Homology, Amino Acid D012737:Sex Factors D013739:Testosterone D013997:Time Factors D014998:Y Chromosome
Medaka Brain Sex differences Sex chromosome cntf pdlim3