Serikawa K A, Zambryski P C
Department of Botany, University of Washington, Seattle 98195, USA.
Plant J. 1997 Apr;11(4):863-9. doi: 10.1046/j.1365-313x.1997.11040863.x.
Domain exchange constructs that traded regions surrounding the homeodomain were constructed for two kn1-like genes, KNAT1 and KNAT3, and introduced into Arabidopsis thaliana under the control of the 35S CaMV promoter. The kn1-like homeodomain proteins all have the homeodomain located near the C-terminus of the protein, and also share a second conserved domain (the ELK domain) immediately N-terminal to the homeodomain. Progeny were scored for the appearance of the KNAT1 overexpression phenotype. A construct containing the KNAT3 N-terminus and the KNAT1 ELK- and homeodomain resulted in a KNAT1 overexpression phenotype, indicating that specificity mainly resides within the ELK- and homeodomain region. Further exchanges demonstrated that specificity probably does not arise from a single region within the ELK and/or homeodomain but rather requires sequences both N-terminal and C-terminal to residue 23 of the homeodomain. Further, in contrast to some animal homeodomains, KNAT1 does not utilize the residues of the N-terminal arm of the homeodomain for specificity.
针对两个类kn1基因KNAT1和KNAT3构建了交换围绕同源异型结构域周围区域的结构域交换构建体，并在35S CaMV启动子的控制下导入拟南芥。类kn1同源异型结构域蛋白的同源异型结构域均位于蛋白的C端附近，并且在同源异型结构域的紧邻N端还共享一个第二个保守结构域（ELK结构域）。对后代进行评分以观察KNAT1过表达表型的出现。一个包含KNAT3 N端以及KNAT1的ELK结构域和同源异型结构域的构建体导致了KNAT1过表达表型，表明特异性主要存在于ELK结构域和同源异型结构域区域内。进一步的交换表明，特异性可能并非源于ELK结构域和/或同源异型结构域内的单个区域，而是需要同源异型结构域第23位残基的N端和C端序列。此外，与一些动物同源异型结构域不同，KNAT1不利用同源异型结构域N端臂的残基来实现特异性。
