KNOX homeobox genes are sufficient in maintaining cultured cells in an undifferentiated state in rice

Yukihiro Ito, Mitsugu Eiguchi, Nori Kurata
Genesis, 2001, 30(4): 231-238     追溯原文......本站官方QQ群:62473826
shoot meristem; regeneration; development; OSH genes; transformation; Oryza sativa

We produced transgenic rice calli, which constitutively express each of four KNOX family class 1 homeobox genes of rice, OSH1, OSH16, OSH15, and OSH71, and found that constitutive and ectopic expression of such genes inhibits normal regeneration from transformed calli, which showed continuous growth around their shoot-regenerating stages. Transgenic calli transferred onto regeneration medium began to display green spots, a sign of regeneration, but most of the transformants continued to propagate green spots at given stages. In the normal shoot-regeneration process of calli, expression of endogenous OSH1 was restricted in presumptive shoot-regenerating regions of calli and not observed in other areas. This restricted expression pattern should be required for further differentiation of the regenerating shoots. Thus our present results support the proposed function that KNOX family class 1 homeobox genes play a role in the formation and maintenance of the undetermined meristematic state of cells.

KNOX同源异型基因对维持培养细胞处在未分化状态是足够的

我们分别构建了四个KNOX家族I类的分类的水稻四个同源异型基因OSH1、OSH16、OSH15、OSH71的启动子为35S的过表达载体,愈伤分化后各自都能组成型表达。发现这些基因的组成和异位表达能够抑制转基因愈伤组织的正常再生。而只是停留在茎端的再生阶段不断持续生长。转基因愈伤转入再生培养基之后开始有分化标识的绿点出现,但是大部分转化体只是停留这一阶段,持续不断的繁殖绿点。在正常的愈伤再生茎端的过程中,内源的OSH1表达只限定愈伤的特定的再生茎端的区域。该限定的表达模式对再生茎端的进一步分化是必须的。因此我们得出的结果支持了这一结论即KNOX家族的I类同源异基因对处于待定的分生阶段的细胞的形成和维持有重要的作用。


基因列表
  矮秆基因;水稻同源异型盒基因 d6; OSH15;Oskn3
  水稻同源异型盒基因 OSH6
  同源异型盒基因 OSH1; Oskn1
  同源异型盒基因 OSH71; Oskn2