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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #58103
Title: CLONING MAIZE TELOMERES BY COMPLEMENTATION IN SACCHAROMYCES CEREVISIAE

Author
item GARDINER, J - UNIV OF MO
item Coe Jr, Edward
item CHAO, S - UNIV OF MO

Submitted to: Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: To ensure that the maps of the chromosomes of corn completely cover the extent of the gene content of corn, markers are needed for the ends of the chromosomes themselves. In this way, maps of the genes and other DNA sequences can be assured to be inclusive, and application of molecular markers in plant breeding and in gene isolation can be done with full confidence. In addition, knowledge on the DNA structure of chromosome ends is needed in order to understand how the ends are stabilized and controlled in cell division. This paper reports isolation of ends of chromosomes (telomeres) by the use of artificial chromosomes in yeast. The artificial chromosomes incorporated corn DNA, and it was confirmed that the pieces of DNA function as ends and map at the ends of the corn chromosomes from which they came. Seven of the 20 chromosome ends of corn were mapped in these experiments, and sequencing of the DNA revealed complex regions of repeated sequences.

Technical Abstract: Telomeric fragments from maize were cloned by virtue of their ability to function as telomeres in yeast. Nine yeast artificial chromosomes (YACs) were selected on the basis of this function and the presence of sequences hybridizing to the known telomere repeat (CCCTAAA x n) of Arabidopsis. End-digestion experiments on two of the YACS indicated that the functioning ends were terminal. Subclones hybridized to sequences in maize that disappeared during end-digestion, indicating that bona fide maize telomeric segments had been cloned. Endpoints of seven chromosome arms were determined by mapping with one subclone. Another subclone mapped to two centromeric regions. DNA sequencing revealed that both subclones contained CA-rich regions with sporadic occurrences of the telomere repeat and degenerate repeats of it.