Up-regulation of P450arom and down-regulation of Dmrt-1 genes in the temperature-dependent sex reversal from genetic males to phenotypic females in a salamander

• Published in: Development genes and evolution 2006-04, Vol.216 (4), p.224-228
• Main Authors: Sakata, Natsuko, Miyazaki, Kinuko, Wakahara, Masami
• Format: Article
• Language: English
• Subjects: Amino Acid Motifs; Amino Acid Sequence; Animals; Aromatase - genetics; Body Temperature - genetics; Disorders of Sex Development; Dmrt-1; DNA, Complementary; Down-Regulation; Female; Freshwater; Gene Expression Regulation, Enzymologic; Genes; Hynobius retardatus; Male; Molecular Sequence Data; Ovary - enzymology; P450arom; Protein Structure, Tertiary; salamanders and newts; Sequence Homology, Amino Acid; Sex Differentiation - genetics; Sex reversal; sexual development; Temperature; Testis - enzymology; Up-Regulation; Urodela - genetics; Urodela - growth & development
• ISSN: 0949-944X; 1432-041X
• DOI: 10.1007/s00427-005-0053-4

When larvae of the salamander Hynobius retardatus were reared at a high temperature (28°C) during their thermosensitive period (TSP=15-30 days after hatching), all larvae developed to phenotypic females irrespective of their genetic sexes. Hynobius P450 aromatase (P450arom) and Dmrt-1 complementary DNAs were isolated and their expression patterns were analyzed by competitive and conventional reverse transcriptase-polymerase chain reaction. While the P450arom gene was expressed predominantly in the ovary, Dmrt-1 was expressed exclusively in the testis. When larvae were reared at the female-producing temperature (28°C) during the TSP, a strong expression of the P450arom gene and a complete suppression of the Dmrt-1 gene were induced in all experimental larvae. Up-regulation of the P450arom gene and down-regulation of the Dmrt-1 gene even in genetic males constitute a part of the molecular biological cascade for the temperature-dependent sex reversal from genetic males to phenotypic females in this salamander.