Construction and behavior of engineered minichromosomes in maize.
Engineered minichromosomes were constructed in maize by modifying natural A and supernumerary B chromosomes. By using telomere-mediated chromosomal truncation, it was demonstrated that such an approach is feasible for the generation of minichromosomes of normal A chromosomes by selection of spontaneous polyploid events that compensate for the deficiencies produced. B chromosomes are readily fractionated by biolistic transformation of truncating plasmids. Foreign genes were faithfully expressed from integrations into normal B chromosomes and from truncated miniB chromosomes. Site-specific recombination between the terminal transgene on a miniA chromosome and a terminal site on a normal chromosome was demonstrated. It was also found that the miniA chromosome did not pair with its progenitor chromosomes during meiosis, indicating a useful property for such constructs. The miniB chromosomes are faithfully transmitted from one generation to the next but can be changed in dosage in the presence of normal B chromosomes. This approach for construction of engineered chromosomes can be easily extended to other plant species because it does not rely on cloned centromere sequences, which are species-specific. These platforms will provide avenues for studies on plant chromosome structure and function and for future developments in biotechnology and agriculture.
Yu
Weichang
W
Division of Biological Sciences, 117 Tucker Hall, University of Missouri, Columbia, MO 65211, USA.
Han
Fangpu
F
Gao
Zhi
Z
Vega
Juan M
JM
Birchler
James A
JA
D001483:Base Sequence; D002872:Chromosome Deletion; D032461:Chromosomes, Plant / Q000235:genetics*; D004274:DNA, Recombinant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter / Q000235:genetics; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D016615:Telomere / Q000235:genetics; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development
D004274:DNA, Recombinant; D010940:Plant Proteins