Composite insulators: sib pauv lub siab dawb paug rau kev koom tes

Cov kev taw qhia cov nyhuv ntawm insulators tau pom nyob rau hauv cov txiv hmab txiv ntoo ya thwmsim. Thaum transposon gypsy tau muab tso rau hauv qhov chaw daj y hauv cov txiv hmab txiv ntoo yoov (D. melanogaster), cov noob y yog inactivated nyob rau hauv ib co ntaub so ntswg, tab sis tseem active nyob rau hauv lwm tus neeg. Qhov no yog vim hais tias lub transposon gypsy muaj ib tug insulator ib theem zuj zus ntawm ib kawg. Thaum gypsy tau tso rau ntawm qhov chaw sib txawv hauv qhov chaw, nws muaj qhov sib txawv ntawm cov kev ua ntawm noob. Qhov no yog vim qhov kev ua ntawm y noob yog tswj los ntawm plaub qhov kev txhim kho. Thaum lub insulator yog ntxig rau ntawm tus txhawb nqa, nws thaiv cov noob ua kom nyob rau hauv lub tis hniav thiab lub cev cuticle cov ntaub so ntswg (los ntawm cov upstream enhancer), tab sis tsis thaiv y noob qhia nyob rau hauv lub bristles thiab farsal claws ntaub so ntswg (los ntawm downstream enhancer).

Txij li qee qhov kev txhim kho tau nyob rau sab saud ntawm tus txhawb nqa thiab qee qhov qis qis, qhov cuam tshuam ntawm cov insulator tsis nyob ntawm nws qhov chaw txheeb ze rau tus txhawb nqa. Yog li ntawd, yog vim li cas rau lub directionality ntawm lub insulator nyhuv tseem tsis tau tag nrho to taub. Ob loci tau raug txheeb xyuas uas cuam tshuam rau kev ua haujlwm insulator los ntawm kev hloov pauv. S2J(Hw) noob encodes ib nucleoprotein uas paub txog cov insulators; lub insulator tsuas yog ua haujlwm tom qab khi rau cov protein. Thaum cov noob no hloov pauv, txawm hais tias ib qho insulator tau muab tso rau hauv y locus, lub insulator poob nws txoj haujlwm insulating; y yog qhia nyob rau hauv tag nrho cov ntaub so ntswg. Lwm qhov chaw yog mod(mdg4). Kev hloov pauv hauv cov noob no muaj qhov cuam tshuam rau Su(Hw); cov mutants no txhim kho cov nyhuv insulating, ua rau cov insulator cov nyhuv insulating tsis yog - kev taw qhia thiab txuas ntxiv, zoo thaiv cov teebmeem ntawm cov dej ntws thiab cov dej ntws. Ib qho kev piav qhia yog tias Su (Hw) thawj khi rau DNA insulator, muab cov insulator nws cov nyhuv insulating. mod(mdg4) ces khi rau Su(Hw), ua rau lub insulator poob nws insulating nyhuv; qhov hloov pauv mod(mdg4) tsis tuaj yeem khi rau Su(Hw), yog li txhim kho cov insulator cov nyhuv insulating dua.