The function of KNOX proteins in shoot development

KNOX蛋白在茎部发育中的功能植物的生长是由被称为分生组织的小群细胞决定的。分生组织产生植物的叶、枝和花。Knotted1-like homeobox （knox）基因在分生组织和茎中表达，是分生组织功能和叶片形成所必需的。KNOX蛋白对于分生组织身份也是足够的，并且如果表达不当，能够赋予叶片分生组织命运。KNOX蛋白是TALE类转录因子的成员，在动物和植物中是保守的。它们作为生化伙伴与bel1样（BELL）蛋白结合DNA，从而调节转录。拟南芥中有8个KNOX蛋白和13个BELL蛋白。拟议的研究将确定哪个KNOX蛋白与哪个BELL蛋白相互作用，在哪个细胞室和哪个组织中。这些实验将在拟南芥中进行。生化实验还将通过鉴定与KNOX蛋白结合的DNA并跟踪转录谱，确定玉米和水稻中哪些基因受到KNOX蛋白的调控。第三个目标是确定哪些调控序列阻止knox基因在叶片中表达。在玉米中存在一些显性突变体，这些突变体在叶片中错误表达knox基因。在大麦和金鱼鱼中也发现了类似的突变。这些突变在内含子序列中都有重排，内含子序列是基因中不编码蛋白质的部分。分子遗传学实验将确定阻止诺克斯基因在叶片中表达的重要序列。从这些实验中获得的信息将提供对植物结构的理解，并导致提高作物产量。在暑假期间，一名来自旧金山的高中化学老师将与研究生一起参与该项目的生物化学实验。此外，每年春天，PI将把遗传学带到一所农村中学的七年级，观察玉米穗上的遗传比率分离并分离DNA。

Hake, Sarah0445387The function of KNOX proteins in shoot developmentPlant growth is determined by small groups of cells called meristems. Meristems produce the leaves, branches and flowers of the plant. Knotted1-like homeobox (knox) genes are expressed in meristems and stems and are required for meristem function and leaf patterning. KNOX proteins are also sufficient for meristematic identity and are able to confer meristem fate on leaves if expressed inappropriately. KNOX proteins are members of the TALE class of transcription factors that are conserved in animals and plants. They function as biochemical partners with BEL1-like (BELL) proteins to bind DNA and thus regulate transcription. There are eight KNOX proteins and 13 BELL proteins in Arabidopsis. The proposed research will determining which KNOX protein interacts with which BELL protein and in what cell compartment and in what tissue. These experiments will be carried out in Arabidopsis. Biochemical experiments will also determine what genes are regulated by KNOX proteins in maize and rice by identifying the DNA which is bound by KNOX proteins and following transcription profiles. The third aim is to determine what are the regulatory sequences that keep knox genes from being expressed in leaves. A number of dominant mutants exist in maize that misexpress knox genes in leaves. Similar mutations are found in barley and snapdragon. These mutations all have rearrangements in intronic sequences, the part of the gene that does not code for protein. Molecular genetic experiments will determine what are the important sequences that keep knox genes from being expressed in leaves. The information gained from these experiments will provide an understanding of plant architecture and lead to improved crop yields. During the summer, a high school chemistry teacher from San Francisco will join the graduate students on the project to participate in the biochemistry experiments. In addition, the PI will bring genetics to the 7th grade of a rural middle school each spring to look at genetic ratios segregating on maize ears and isolate DNA.