{"id":1703,"date":"2015-01-14T00:09:33","date_gmt":"2015-01-13T22:09:33","guid":{"rendered":"http:\/\/bilimvegelecek.com.tr\/?p=1703"},"modified":"2015-01-14T00:09:33","modified_gmt":"2015-01-13T22:09:33","slug":"kok-hucreden-yumurta-ve-sperm-uretildi","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2015\/01\/14\/kok-hucreden-yumurta-ve-sperm-uretildi","title":{"rendered":"K\u00f6k h\u00fccreden yumurta ve sperm \u00fcretildi"},"content":{"rendered":"<p><em>G\u00f6rsel a\u00e7\u0131klama: Ye\u015fil renge boyanm\u0131\u015f SOX17 geni aktif olan h\u00fccrelerin g\u00f6r\u00fclmeye ba\u015flad\u0131\u011f\u0131 anda bir embriyoid. \u0130\u015faretli h\u00fccreler e\u015fey ana h\u00fccrelerini olu\u015fturacak.<\/em><\/p>\n<p>Cambridge \u00dcniversitesi\u2019ndeki biliminsanlar\u0131 insan embriyonal k\u00f6k h\u00fccrelerinden e\u015fey ana h\u00fccrelerini \u00fcretmeyi ba\u015fard\u0131. Weizmann Enstit\u00fcs\u00fc ile y\u00fcr\u00fct\u00fclen \u00e7al\u0131\u015fmada, ilk defa insan k\u00f6k h\u00fccresi kullan\u0131larak insan e\u015fey ana h\u00fccreleri \u00fcretildi. Bu \u00e7al\u0131\u015fma daha \u00f6nce fare k\u00f6k h\u00fccreleri kullan\u0131larak yap\u0131l\u0131p olumlu sonu\u00e7 al\u0131nm\u0131\u015ft\u0131.<br \/>\nYumurta, sperm taraf\u0131ndan d\u00f6llendikten yakla\u015f\u0131k 5 g\u00fcn sonra blastosit ad\u0131 verilen h\u00fccre yuma\u011f\u0131na d\u00f6n\u00fc\u015f\u00fcr. Geli\u015fimin ilerleyen evrelerinde ise blastosit i\u00e7 ve d\u0131\u015f h\u00fccre k\u00fcmelerine d\u00f6n\u00fc\u015f\u00fcr. Olu\u015fan d\u0131\u015f h\u00fccre k\u00fcmesi plasentaya d\u00f6n\u00fc\u015fecekken i\u00e7 h\u00fccre k\u00fcmesi de fetusu yani do\u011facak bireyi olu\u015fturacak olan k\u00f6k h\u00fccrelere d\u00f6n\u00fc\u015fecektir. Bu k\u00f6k h\u00fccreler ilerleyen zamanlarda fetusta bulunma yerlerine g\u00f6re \u00f6zelle\u015fecek olup, dokular\u0131 ve organlar\u0131 olu\u015fturacakt\u0131r. Bu h\u00fccrelerin k\u00fc\u00e7\u00fck bir k\u0131sm\u0131 e\u015fey ana h\u00fccrelerine d\u00f6n\u00fc\u015fecektir. Genetik materyal, buradan \u00fcretilen spermler ve yumurtalar sayesinde gelecek nesillere aktar\u0131l\u0131r.<br \/>\n\u00c7al\u0131\u015fman\u0131n ba\u015fyazar\u0131 Dr. Naoko Irie konuyla ilgili \u015funlar\u0131 s\u00f6yledi: \u201cMemeli geli\u015fiminin en erken a\u015famalar\u0131ndan biri e\u015fey ana h\u00fccrelerinin olu\u015fumudur. Bu y\u00f6ntemi daha \u00f6nce fare ve s\u0131\u00e7anlarda kullan\u0131p ba\u015far\u0131ya ula\u015fm\u0131\u015ft\u0131k, ama \u015fu ana kadar \u00e7ok az sistematik \u00e7al\u0131\u015fmada insan h\u00fccreleri kullan\u0131ld\u0131. Bu \u00e7al\u0131\u015fma ile insan ve fare embriyonal geli\u015fmeleri aras\u0131nda \u00f6nemli farkl\u0131l\u0131klar oldu\u011funu g\u00f6zlemledik ve dolay\u0131s\u0131yla farelerde al\u0131nan sonu\u00e7lar\u0131n insanlarda do\u011frudan kullan\u0131lmamas\u0131 gerekti\u011fini \u00f6\u011frendik.\u201d<br \/>\n\u00c7al\u0131\u015fman\u0131n \u00f6nc\u00fcs\u00fc Prof. Surani ve arkada\u015flar\u0131, SOX17 adl\u0131 genin insanlarda k\u00f6k h\u00fccrelerin e\u015fey ana h\u00fccrelerine d\u00f6n\u00fc\u015fmesinde kritik rol oynad\u0131\u011f\u0131n\u0131 buldu. Bu bulgu asl\u0131nda b\u00fcy\u00fck bir s\u00fcrpriz niteli\u011fi ta\u015f\u0131yordu, \u00e7\u00fcnk\u00fc bu genin farelerdeki dengi bu i\u015flevde g\u00f6rev almamakta. Farelerin ve insanlar\u0131n geli\u015fiminde kilit farkl\u0131l\u0131klar oldu\u011fu da g\u00f6r\u00fcld\u00fc. SOX17 geninin k\u00f6k h\u00fccreleri, i\u00e7 organlar\u0131 olu\u015fturacak olan endoderm h\u00fccrelerine d\u00f6n\u00fc\u015ft\u00fcrd\u00fc\u011f\u00fc biliniyordu, ama ilk defa e\u015fey ana h\u00fccresi olu\u015fumunda rol ald\u0131\u011f\u0131 g\u00f6zlendi.<br \/>\nGrup ayr\u0131ca v\u00fccut h\u00fccrelerini geri programlayarak e\u015fey ana h\u00fccreleri olu\u015fturulabilece\u011fini ve bu bulgunun insan \u00fcreme sistemi, k\u0131s\u0131rl\u0131k ve e\u015fey h\u00fccreleri t\u00fcm\u00f6rleri konusunda \u00e7al\u0131\u015fmalarda kullan\u0131labilece\u011fini g\u00f6sterdi. \u00c7al\u0131\u015fman\u0131n \u0131\u015f\u0131k tutabilece\u011fi noktalardan birisi ise epigenetik miras s\u00fcreci. Biliminsanlar\u0131 bir s\u00fcredir \u00e7evremizin ve ya\u015fant\u0131m\u0131z\u0131n (sigara i\u00e7mek, beslenme al\u0131\u015fkanl\u0131klar\u0131 vs.) genlerimizin aktiflik seviyesini metilasyon sayesinde artt\u0131r\u0131p azaltabilece\u011fini bilmekte. Metilasyon DNA\u2019ya molek\u00fcl ba\u011flanmas\u0131 sonucu, genin aktiflik seviyesinin art\u0131p azalmas\u0131 durumudur ve bu metilasyon kal\u0131plar\u0131 bir sonraki nesle aktar\u0131labilir. Prof. Surani bu \u00e7al\u0131\u015fmada e\u015fey ana h\u00fccresi olu\u015fumunda metilasyon kal\u0131plar\u0131n\u0131 silen bir mekanizman\u0131n oldu\u011funu, ama metilasyon kal\u0131plar\u0131n\u0131n bir k\u0131sm\u0131n\u0131n yine de aktarilabilece\u011fini ve bu aktar\u0131m\u0131n sebebinin bilinmedi\u011fini de s\u00f6yledi.<br \/>\n\u201cE\u015fey h\u00fccreleri, jenerasyonlar aras\u0131nda sa\u011flam ba\u011flant\u0131lar olu\u015fturdu\u011fu ve genetik materyali nesilden nesle aktard\u0131\u011f\u0131 i\u00e7in pratikte ebedidir. Epigenetik mutasyonlar\u0131n sonraki nesle ge\u00e7erken \u00e7o\u011funun silinmesi o t\u00fcr\u00fcn soy a\u011fac\u0131nda yenilenme sa\u011flamakta ve sonsuz nesiller verebilmesini sa\u011flamakta. Bu mekanizmalar da genellikle ya\u015f ile alakal\u0131 hastal\u0131klar\u0131n anla\u015f\u0131lmas\u0131nda kullan\u0131lmakta \u00e7\u00fcnk\u00fc bu hastal\u0131klar\u0131n epigenetik mutasyonlar\u0131n birikimi ile olu\u015ftu\u011funu d\u00fc\u015f\u00fcn\u00fcyoruz.\u201d<\/p>\n<p><strong>\u00c7eviren: Nazif Ta\u015fba\u015f<br \/>\n<em>\u0130T\u00dc Molek\u00fcler Biyoloji ve Genetik B\u00f6l\u00fcm\u00fc<\/strong><\/em><\/p>\n<p><strong>Kaynak:<\/strong> http:\/\/www.sciencedaily.com\/releases\/2014\/12\/141225143546.htm<\/p>\n","protected":false},"excerpt":{"rendered":"<p>G\u00f6rsel a\u00e7\u0131klama: Ye\u015fil renge boyanm\u0131\u015f SOX17 geni aktif olan h\u00fccrelerin g\u00f6r\u00fclmeye ba\u015flad\u0131\u011f\u0131 anda bir embriyoid. \u0130\u015faretli h\u00fccreler e\u015fey ana h\u00fccrelerini olu\u015fturacak. Cambridge \u00dcniversitesi\u2019ndeki biliminsanlar\u0131 insan embriyonal k\u00f6k h\u00fccrelerinden e\u015fey ana h\u00fccrelerini \u00fcretmeyi ba\u015fard\u0131. Weizmann Enstit\u00fcs\u00fc ile y\u00fcr\u00fct\u00fclen \u00e7al\u0131\u015fmada, ilk defa insan k\u00f6k h\u00fccresi kullan\u0131larak insan e\u015fey ana h\u00fccreleri \u00fcretildi. Bu \u00e7al\u0131\u015fma daha \u00f6nce fare k\u00f6k [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":1704,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19,231],"tags":[],"class_list":["post-1703","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","category-molekuler-biyoloji-ve-genetik"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/1703","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/comments?post=1703"}],"version-history":[{"count":0,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/1703\/revisions"}],"wp:attachment":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media?parent=1703"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/categories?post=1703"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/tags?post=1703"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}