Tam­ing of shrew

China Daily (Hong Kong) - - FRONT PAGE - By CHENG YINGQI chengy­ingqi@chi­nadaily.com.cn

Sci­en­tists have made the first ge­net­i­cally mod­i­fied tree shrews for ex­per­i­men­tal use.

Chi­nese sci­en­tists have de­vel­oped meth­ods to make the world’s first ge­net­i­cally mod­i­fied tree shrews, paving the way for the pro­duc­tion of “knock­out” tree shrews for ex­per­i­men­tal use, ac­cord­ing to re­search paper pub­lished by Cell Re­search, a monthly peer­re­viewed sci­en­tific jour­nal by the Na­ture Pub­lish­ing Group.

The tree shrew, a small, fluffy mam­mal that looks like a squir­rel, is an ideal lab­o­ra­tory an­i­mal be­cause it shares a higher de­gree of sim­i­lar­i­ties with hu­mans than rats do. How­ever, the species’ timid­ity has pre­vented it from con­tribut­ing to stud­ies on hu­man health.

“The tree shrew has a nerv- ous sys­tem and an im­mune sys­tem that share many more sim­i­lar­i­ties with pri­mates, mak­ing it suit­able for med­i­cal re­search on neu­ro­log­i­cal dis­eases and in­fec­tious dis­eases,” said Zheng Ping, a re­searcher at the Kun­ming In­sti­tute of Zool­ogy af­fil­i­ated to the Chi­nese Acad­emy of Sciences, and an au­thor of the re­search paper.

How­ever, ef­forts to pro­duce knock­out tree shrews, which have a gene re­moved or re­placed in or­der to change their ap­pear­ance, be­hav­ior or other char­ac­ter­is­tics, have failed. “One rea­son lies in the lack of prac­ti­cal gene ma­nip­u­la­tion tech­niques,” said Li Chao­hui, a PhD stu­dent and another au­thor of the re­search paper.

Sci­en­tists have lit­tle knowl- edge about the re­pro­duc­tive bi­ol­ogy of the species, so it is dif­fi­cult to take their em­bry­onic stem cells or trans­plant ge­net­i­cally mod­i­fied em­bryos into the womb.

“In ad­di­tion, tree shrews are eas­ily fright­ened. They have a stress re­sponse dur­ing surgery — some­times re­sult­ing in death — that makes it al­most im­pos­si­ble to im­preg­nate them in such con­di­tions,” Li said.

Due to such cir­cum­stances, the team be­gan ex­per­i­ment­ing with male tree shrews. They added cell sur­face mark­ers into their sper­mato­go­nial stem cells, and if a par­tic­u­lar gene was ex­pressed, the skin pig­ment of the off­spring of ge­net­i­cally mod­i­fied tree shrews would ap­pear green un­der ul­tra­vi­o­let light.

“The next step is to knock out a tree shrew’s gene, such as a gene re­lated to Alzheimer's dis­ease, for re­search pur­poses,” Zheng said.

PRO­VIDED TO CHINA DAILY

Ex­perts at the Kun­ming In­sti­tute of Zool­ogy in Yun­nan prov­ince say they have found a way to pro­duce ge­net­i­cally mod­i­fied tree shrews, which could be used to find so­lu­tions to hu­man health prob­lems.

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