Precise responses to changes in light quality are crucial for plant growth and development.For example,hypocotyls of shade-avoiding plants typically elongate under shade conditions.Although this typical shade-avoidanc...Precise responses to changes in light quality are crucial for plant growth and development.For example,hypocotyls of shade-avoiding plants typically elongate under shade conditions.Although this typical shade-avoidance response(TSR)has been studied in Arabidopsis(Arabidopsis thaliana),the molecular mechanisms underlying shade tolerance are poorly understood.Here we report that B.napus(Brassica napus)seedlings exhibit dual shade responses.In addition to the TSR,B.napus seedlings also display an atypical shade response(ASR),with shorter hypocotyls upon perception of early-shade cues.Genome-wide selective sweep analysis indicated that ASR is associated with light and auxin signaling.Moreover,genetic studies demonstrated that phytochrome A(BnphyA)promotes ASR,whereas BnphyB inhibits it.During ASR,YUCCA8 expression is activated by early-shade cues,leading to increased auxin biosynthesis.This inhibits hypocotyl elongation,as young B.napus seedlings are highly sensitive to auxin.Notably,two non-canonical AUXIN/INDOLE-3-ACETIC ACID(Aux/IAA)repressor genes,BnIAA32 and BnIAA34,are expressed during this early stage.BnIAA32 and BnIAA34 inhibit hypocotyl elongation under shade conditions,and mutations in BnIAA32 and BnIAA34 suppress ASR.Collectively,our study demonstrates that the temporal expression of BnIAA32 and BnIAA34 determines the behavior of B.napus seedlings following shade-induced auxin biosynthesis.展开更多
A series of retroviral vectors encoding human mdrl gene alone as well as in combination with either human mgmt gene or human mutant Ser31-dftfrgene are engineered. The resultant retroviruses are used to transduce huma...A series of retroviral vectors encoding human mdrl gene alone as well as in combination with either human mgmt gene or human mutant Ser31-dftfrgene are engineered. The resultant retroviruses are used to transduce human umbilical cord blood CD34+ cells. It has been shown that expression of dual drug resistance genes in transduced cells confers a broad range of resistance to both kinds of corresponding drugs. These data suggest a rationale for the use of such double chemoresistance gene constructs in an in vivo model in which transduced hematopoietic cells will acquire multiple protection against the cytotoxic side effects of combination chemotherapy and may have future application in chemoprotection of normal tissues, thus killing tumor cells more effectively.展开更多
基金supported by the Scientific Innovation 2030 Project(2022ZD0400801)the National Key R&D Program of China(2022YFD1200400)+1 种基金the National Natural Science Foundation of China(32100190)the National Natural Science Fund for Excellent Young Scientists Fund Program(Overseas).
文摘Precise responses to changes in light quality are crucial for plant growth and development.For example,hypocotyls of shade-avoiding plants typically elongate under shade conditions.Although this typical shade-avoidance response(TSR)has been studied in Arabidopsis(Arabidopsis thaliana),the molecular mechanisms underlying shade tolerance are poorly understood.Here we report that B.napus(Brassica napus)seedlings exhibit dual shade responses.In addition to the TSR,B.napus seedlings also display an atypical shade response(ASR),with shorter hypocotyls upon perception of early-shade cues.Genome-wide selective sweep analysis indicated that ASR is associated with light and auxin signaling.Moreover,genetic studies demonstrated that phytochrome A(BnphyA)promotes ASR,whereas BnphyB inhibits it.During ASR,YUCCA8 expression is activated by early-shade cues,leading to increased auxin biosynthesis.This inhibits hypocotyl elongation,as young B.napus seedlings are highly sensitive to auxin.Notably,two non-canonical AUXIN/INDOLE-3-ACETIC ACID(Aux/IAA)repressor genes,BnIAA32 and BnIAA34,are expressed during this early stage.BnIAA32 and BnIAA34 inhibit hypocotyl elongation under shade conditions,and mutations in BnIAA32 and BnIAA34 suppress ASR.Collectively,our study demonstrates that the temporal expression of BnIAA32 and BnIAA34 determines the behavior of B.napus seedlings following shade-induced auxin biosynthesis.
文摘A series of retroviral vectors encoding human mdrl gene alone as well as in combination with either human mgmt gene or human mutant Ser31-dftfrgene are engineered. The resultant retroviruses are used to transduce human umbilical cord blood CD34+ cells. It has been shown that expression of dual drug resistance genes in transduced cells confers a broad range of resistance to both kinds of corresponding drugs. These data suggest a rationale for the use of such double chemoresistance gene constructs in an in vivo model in which transduced hematopoietic cells will acquire multiple protection against the cytotoxic side effects of combination chemotherapy and may have future application in chemoprotection of normal tissues, thus killing tumor cells more effectively.
