Cov kws tshawb nrhiav pom cov txheej txheem ntawm DELLA protein tswj hwm hauv cov nroj tsuag.

Cov kws tshawb fawb los ntawm Department of Biochemistry ntawm Indian Institute of Sciences (IISc) tau tshawb pom ib txoj hauv kev uas cov nroj tsuag hauv av qub xws li bryophytes (suav nrog mosses thiab liverworts) siv los ua kom muaj kev hloov pauv ntawm cov kab mob.tswj kev loj hlob ntawm cov nroj tsuag- ib txoj hauv kev uas tau khaws cia rau hauv cov nroj tsuag uas nyuam qhuav tsim paj.

Txoj kev tshawb fawb no, luam tawm hauv phau ntawv xov xwm Nature Chemical Biology, tsom mus rau kev tswj hwm tsis yog classical ntawm DELLA protein, uas yog tus tswj kev loj hlob uas tuaj yeem tiv thaiv kev faib cell hauv cov nroj tsuag embryonic (cov nroj tsuag hauv av).
"DELLA ua haujlwm zoo li lub pob nrawm, tab sis yog tias lub pob nrawm no nyob tas li, cov nroj tsuag yuav tsis txav tau," piav qhia Debabrata Laha, tus xibfwb qhia txog biochemistry thiab tus sau ntawv ntawm txoj kev tshawb fawb. Yog li ntawd, kev puas tsuaj ntawm DELLA cov protein yog qhov tseem ceeb rau kev txhawb nqa kev loj hlob ntawm cov nroj tsuag. Hauv cov nroj tsuag paj, DELLA raug puas tsuaj thaum phytohormonegibberellin (GA)khi rau nws lub receptor GID1, tsim cov GA-GID1-DELLA complex. Tom qab ntawd, cov protein DELLA repressor khi rau ubiquitin chains thiab raug rhuav tshem los ntawm 26S proteasome.
Qhov txaus nyiam yog tias cov bryophytes yog cov nroj tsuag thawj zaug uas tau nyob hauv av, kwv yees li 500 lab xyoo dhau los. Txawm hais tias lawv tsim cov phytohormone gibberellin (GA), lawv tsis muaj GID1 receptor. Qhov no ua rau muaj lus nug: kev loj hlob thiab kev txhim kho ntawm cov nroj tsuag av thaum ntxov no tau tswj hwm li cas?
Cov kws tshawb nrhiav tau siv lub tshuab CRISPR-Cas9 los rhuav tshem cov noob caj noob ces VIH, yog li ntawd lees paub lub luag haujlwm ntawm VIH. Cov nroj tsuag uas tsis muaj cov enzyme VIH ua haujlwm qhia txog kev loj hlob thiab kev loj hlob tsis zoo thiab cov qauv tsis zoo, xws li thallus ntom ntom, kev loj hlob radial tsis zoo, thiab tsis muaj calyx. Cov kev tsis zoo no tau kho los ntawm kev hloov kho cov noob caj noob ces ntawm cov nroj tsuag kom tsim tau ib qho kawg (N-terminus) ntawm cov enzyme VIH. Siv cov txheej txheem chromatography siab heev, pab pawg tshawb fawb tau pom tias N-terminus muaj ib qho kinase domain uas ua rau muaj InsP₈.
Cov kws tshawb nrhiav tau pom tias DELLA yog ib qho ntawm cov hom phiaj ntawm VIH kinase. Ntxiv mus, lawv tau pom tias cov qauv ntawm cov nroj tsuag MpVIH-deficient zoo ib yam li cov nroj tsuag Miscanthus multiforme nrog kev nce ntxiv ntawm DELLA.
"Nyob rau theem no, peb xav txiav txim siab seb DELLA qhov ruaj khov lossis kev ua haujlwm puas tau txhim kho hauv cov nroj tsuag uas tsis muaj MpVIH," Priyanshi Rana, tus tub ntxhais kawm qib siab hauv Lahey pawg tshawb fawb thiab tus sau thawj zaug ntawm daim ntawv hais. Sib xws nrog lawv qhov kev xav, cov kws tshawb fawb pom tias DELLA inhibition tau kho qhov kev loj hlob thiab kev txhim kho tsis zoo hauv cov nroj tsuag MpVIH mutant. Cov kev tshawb pom no qhia tias VIH kinase tswj hwm DELLA tsis zoo, yog li txhawb nqa kev loj hlob thiab kev txhim kho ntawm cov nroj tsuag.
Cov kws tshawb fawb tau muab cov txheej txheem kev tshuaj ntsuam genetic, biochemical, thiab biophysical ua ke los piav qhia txog txoj hauv kev uas inositol pyrophosphate tswj hwm DELLA protein kev qhia tawm hauv bryophyte no. Tshwj xeeb, InsP₈, tsim los ntawm MpVIH, khi rau MpDELLA protein, txhawb nws cov polyubiquitination, uas ua rau muaj kev puas tsuaj ntawm cov protein repressor no los ntawm proteasome.
Kev tshawb fawb txog cov protein DELLA tau pib txij li thaum Lub Caij Hloov Pauv Ntsuab, thaum cov kws tshawb fawb tsis paub siv nws lub peev xwm los tsim cov hom semi-dwarf uas muaj txiaj ntsig zoo. Txawm hais tias nws txoj kev ua haujlwm tsis tau paub thaum lub sijhawm ntawd, cov thev naus laus zis niaj hnub no tau ua rau cov kws tshawb fawb siv kev kho cov noob caj noob ces los tswj hwm kev ua haujlwm ntawm cov protein no, yog li ua rau cov qoob loo ntau ntxiv.
"Nrog rau kev loj hlob ntawm cov pej xeem thiab kev txo qis ntawm thaj av ua liaj ua teb, kev nce qoob loo tau dhau los ua qhov tseem ceeb," Raha hais. Vim tias InsP₈-tswj DELLA degradation tuaj yeem kis tau dav hauv cov nroj tsuag embryonic, qhov kev tshawb pom no tuaj yeem ua rau txoj hauv kev rau kev txhim kho cov qoob loo siab rau tiam tom ntej.