Mutations in the binding sites depress the enhancer activities of <i>Tokudaia</i> TESCO.

<p>Mutated TESCO, in which all binding sites were replaced by mouse sequence, showed recovery of activities by co-transfection of TMU_SOX9 and SF1. However, no significant activity was observed by TMU_SRY. Means and standard deviations from at least three independent experiments are shown. *<i>P</i><0.05.</p

The identity of TESCO sequences.

<p>The identity of TESCO sequences.</p

Evolution of the Y chromosome and sex-determining mechanism in the genus <i>Tokudaia</i>.

<p>Nucleotide substitutions accumulated in SRY and SF1 binding sites in TESCO of the common ancestor after emergence of a new sex-determining gene, leading to inactivation of TESCO, and SRY could not function as a transcription factor. In the common ancestor or in a lineage of <i>T. muenninki</i>, SRY itself lost function caused by mutations in the <i>SRY</i> sequence. Neo-X and neo-Y chromosomes were acquired by fusion of a pair of autosomes with the X and Y chromosomes. Many pseudo SRY copies amplified and were distributed throughout the heterochromatic region in the neo-Y chromosome. In a common ancestor of <i>T. osimensis</i> and <i>T. tokunosimensis</i>, a part of the Y region translocated to the distal region of X chromosome and the remaining Y chromosome region containing <i>SRY</i> (and other genes) was completely lost.</p

Impaired transcription factor function of <i>T. muenninki</i> SRY.

<p>(A) Comparison of the enhancer activity of mouse TESCO by co-transfecting mSRY with SF1 and TMU_SRY with SF1. <i>T. muenninki</i> SRY did not increase the activity of mouse TESCO. (B) One amino acid substitution at the 21st position within HMG-box had no effect on the function of <i>T. muenninki</i> SRY. The TMU_SRY_StoA also did not increase the activity of mouse TESCO. Means and standard deviations from at least three independent experiments are shown.</p

L'Alerte : journal indépendant : politique, littéraire et commercial

11 mai 19081908/05/11 (A12)-1908/05/11