科學家可能發(fā)現(xiàn)了導致小鼠的毛發(fā)周期性脫落的遺傳機制，而且提出同樣的原因可能造成的人類毛發(fā)脫落,，即脫發(fā)癥,。通常，毛發(fā)經歷了一個生長,、靜止和脫落的過程,，之后生長重新開始。
Yumiko Saga和同事報告說,，缺乏Sox21基因的小鼠表現(xiàn)出了從頭到尾的進行性的毛發(fā)脫落,、幾天后毛發(fā)重新生長的循環(huán)。這組作者發(fā)現(xiàn),，Sox21幫助調控了角蛋白——毛發(fā)的蛋白質基本成分——的合成,，而且證明了沒有這個基因的小鼠與Sox21基因水平正常的小鼠相比，前者的毛發(fā)構建蛋白減少,。這種遺傳改造小鼠還在毛囊周圍有增大的分泌油的皮脂腺,，而且在毛發(fā)脫落期的皮膚細胞層變厚。這組作者提出，這個基因很可能參與了形成毛干的外層的干細胞的分化,。對人類皮膚樣本的檢查證實了在毛發(fā)外層Sox21基因的高度表達,。這組作者得出結論說，這些結果表明Sox21基因可能導致了人類的一些毛發(fā)脫落病癥,。（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS May 26, 2009, doi: 10.1073/pnas.0808324106
The disruption of Sox21-mediated hair shaft cuticle differentiation causes cyclic alopecia in mice
Makoto Kisoa,1, Shigekazu Tanakab,1, Rie Sabaa, Satoru Matsudac, Atsushi Shimizud, Manabu Ohyamad, Hirotaka James Okanoc, Toshihiko Shiroishib,e, Hideyuki Okanoc and Yumiko Sagaa,e,2
Hair is maintained through a cyclic process that includes periodic regeneration of hair follicles in a stem cell-dependent manner. Little is known, however, about the cellular and molecular mechanisms that regulate the layered differentiation of the hair follicle. We have established a mutant mouse with a cyclic alopecia phenotype resulting from the targeted disruption of Sox21, a gene that encodes a HMG-box protein. These mice exhibit progressive hair loss after morphogenesis of the first hair follicle and become completely nude in appearance, but then show hair regrowth. Sox21 is expressed in the cuticle layer and the progenitor cells of the hair shaft in both mouse and human. The lack of this gene results in a loss of the interlocking structures required for anchoring the hair shaft in the hair follicle. Furthermore, the expression of genes encoding the keratins and keratin binding proteins in the hair shaft cuticle are also specifically down-regulated in the Sox21-null mouse. These results indicate that Sox21 is a master regulator of hair shaft cuticle differentiation and shed light on the possible causes of human hair disorders.
