De novo synthesis of telomere sequences at the healed breakpoints of wheat deletion chromosomes

H. Tsujimoto, N. Usami, K. Hasegawa, T. Yamada, Kiyotaka Nagaki, T. Sasakuma

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

When chromosomes are broken, the breakpoints become highly unstable and acquire the ability to fuse with other broken ends. The breakpoints are, however, eventually stabilized, and, therefore, the broken chromosomes are transmitted to the daughter cells without further morphological change. This phenomenon, known as 'healing of breakpoints', involves the addition of repetitive telomere sequences at the breakpoints by telomerase, the enzyme that normally synthesizes the telomere sequence at normal chromosome terminals. In many higher organisms, however, this property has not been well investigated. In this study, we examined the telomere sequences in wheat deletion lines with breakpoints on chromosome 1B. Lines that had breakpoints around the nucleolar organizer region were first selected on the basis of cytological observations, and the precise breakpoints were determined by mapping a fragment of rDNA and RFLP markers. In three lines - in addition to one previously reported - the DNA fragments encompassing the breakpoints were amplified by PCR using primers located in the rDNA and in telomere sequences. The DNA sequences provide insight into the properties of the telomerase activity at the breakpoints. The telomere sequences initiated from 2- to 4-nucleotide motifs in the original ribosomal DNA sequence which are also found in the repeat unit characteristic of telomere sequences. No specific sequences or structures were observed at or around the breakpoints. At all of the four breakpoints investigated, the newly synthesized telomere sequences contained considerable numbers of atypical telomere sequence units, particularly TTAGGG, which is the common unit of mammalian telomere sequences. Based on these results, we discuss the ability of plant telomerase to initiate the de novo synthesis of telomere sequences at internal breakpoints.

Original languageEnglish
Pages (from-to)851-856
Number of pages6
JournalMGG Molecular & General Genetics
Volume262
Issue number4-5
DOIs
Publication statusPublished - 1999
Externally publishedYes

Fingerprint

Chromosome Deletion
Telomere
Triticum
Telomerase
Ribosomal DNA
Chromosome Breakpoints
Chromosomes
Nucleolus Organizer Region
Nucleotide Motifs
Nucleic Acid Repetitive Sequences
Restriction Fragment Length Polymorphisms
Polymerase Chain Reaction

Keywords

  • Chromosome breakage
  • Chromosome healing
  • Gametocidal gene
  • Telomerase
  • Triticum aestivum

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology

Cite this

De novo synthesis of telomere sequences at the healed breakpoints of wheat deletion chromosomes. / Tsujimoto, H.; Usami, N.; Hasegawa, K.; Yamada, T.; Nagaki, Kiyotaka; Sasakuma, T.

In: MGG Molecular & General Genetics, Vol. 262, No. 4-5, 1999, p. 851-856.

Research output: Contribution to journalArticle

Tsujimoto, H. ; Usami, N. ; Hasegawa, K. ; Yamada, T. ; Nagaki, Kiyotaka ; Sasakuma, T. / De novo synthesis of telomere sequences at the healed breakpoints of wheat deletion chromosomes. In: MGG Molecular & General Genetics. 1999 ; Vol. 262, No. 4-5. pp. 851-856.
@article{b8c878de820e4970a2e965a85bfe9450,
title = "De novo synthesis of telomere sequences at the healed breakpoints of wheat deletion chromosomes",
abstract = "When chromosomes are broken, the breakpoints become highly unstable and acquire the ability to fuse with other broken ends. The breakpoints are, however, eventually stabilized, and, therefore, the broken chromosomes are transmitted to the daughter cells without further morphological change. This phenomenon, known as 'healing of breakpoints', involves the addition of repetitive telomere sequences at the breakpoints by telomerase, the enzyme that normally synthesizes the telomere sequence at normal chromosome terminals. In many higher organisms, however, this property has not been well investigated. In this study, we examined the telomere sequences in wheat deletion lines with breakpoints on chromosome 1B. Lines that had breakpoints around the nucleolar organizer region were first selected on the basis of cytological observations, and the precise breakpoints were determined by mapping a fragment of rDNA and RFLP markers. In three lines - in addition to one previously reported - the DNA fragments encompassing the breakpoints were amplified by PCR using primers located in the rDNA and in telomere sequences. The DNA sequences provide insight into the properties of the telomerase activity at the breakpoints. The telomere sequences initiated from 2- to 4-nucleotide motifs in the original ribosomal DNA sequence which are also found in the repeat unit characteristic of telomere sequences. No specific sequences or structures were observed at or around the breakpoints. At all of the four breakpoints investigated, the newly synthesized telomere sequences contained considerable numbers of atypical telomere sequence units, particularly TTAGGG, which is the common unit of mammalian telomere sequences. Based on these results, we discuss the ability of plant telomerase to initiate the de novo synthesis of telomere sequences at internal breakpoints.",
keywords = "Chromosome breakage, Chromosome healing, Gametocidal gene, Telomerase, Triticum aestivum",
author = "H. Tsujimoto and N. Usami and K. Hasegawa and T. Yamada and Kiyotaka Nagaki and T. Sasakuma",
year = "1999",
doi = "10.1007/s004380051150",
language = "English",
volume = "262",
pages = "851--856",
journal = "Molecular Genetics and Genomics",
issn = "1617-4615",
publisher = "Springer Verlag",
number = "4-5",

}

TY - JOUR

T1 - De novo synthesis of telomere sequences at the healed breakpoints of wheat deletion chromosomes

AU - Tsujimoto, H.

AU - Usami, N.

AU - Hasegawa, K.

AU - Yamada, T.

AU - Nagaki, Kiyotaka

AU - Sasakuma, T.

PY - 1999

Y1 - 1999

N2 - When chromosomes are broken, the breakpoints become highly unstable and acquire the ability to fuse with other broken ends. The breakpoints are, however, eventually stabilized, and, therefore, the broken chromosomes are transmitted to the daughter cells without further morphological change. This phenomenon, known as 'healing of breakpoints', involves the addition of repetitive telomere sequences at the breakpoints by telomerase, the enzyme that normally synthesizes the telomere sequence at normal chromosome terminals. In many higher organisms, however, this property has not been well investigated. In this study, we examined the telomere sequences in wheat deletion lines with breakpoints on chromosome 1B. Lines that had breakpoints around the nucleolar organizer region were first selected on the basis of cytological observations, and the precise breakpoints were determined by mapping a fragment of rDNA and RFLP markers. In three lines - in addition to one previously reported - the DNA fragments encompassing the breakpoints were amplified by PCR using primers located in the rDNA and in telomere sequences. The DNA sequences provide insight into the properties of the telomerase activity at the breakpoints. The telomere sequences initiated from 2- to 4-nucleotide motifs in the original ribosomal DNA sequence which are also found in the repeat unit characteristic of telomere sequences. No specific sequences or structures were observed at or around the breakpoints. At all of the four breakpoints investigated, the newly synthesized telomere sequences contained considerable numbers of atypical telomere sequence units, particularly TTAGGG, which is the common unit of mammalian telomere sequences. Based on these results, we discuss the ability of plant telomerase to initiate the de novo synthesis of telomere sequences at internal breakpoints.

AB - When chromosomes are broken, the breakpoints become highly unstable and acquire the ability to fuse with other broken ends. The breakpoints are, however, eventually stabilized, and, therefore, the broken chromosomes are transmitted to the daughter cells without further morphological change. This phenomenon, known as 'healing of breakpoints', involves the addition of repetitive telomere sequences at the breakpoints by telomerase, the enzyme that normally synthesizes the telomere sequence at normal chromosome terminals. In many higher organisms, however, this property has not been well investigated. In this study, we examined the telomere sequences in wheat deletion lines with breakpoints on chromosome 1B. Lines that had breakpoints around the nucleolar organizer region were first selected on the basis of cytological observations, and the precise breakpoints were determined by mapping a fragment of rDNA and RFLP markers. In three lines - in addition to one previously reported - the DNA fragments encompassing the breakpoints were amplified by PCR using primers located in the rDNA and in telomere sequences. The DNA sequences provide insight into the properties of the telomerase activity at the breakpoints. The telomere sequences initiated from 2- to 4-nucleotide motifs in the original ribosomal DNA sequence which are also found in the repeat unit characteristic of telomere sequences. No specific sequences or structures were observed at or around the breakpoints. At all of the four breakpoints investigated, the newly synthesized telomere sequences contained considerable numbers of atypical telomere sequence units, particularly TTAGGG, which is the common unit of mammalian telomere sequences. Based on these results, we discuss the ability of plant telomerase to initiate the de novo synthesis of telomere sequences at internal breakpoints.

KW - Chromosome breakage

KW - Chromosome healing

KW - Gametocidal gene

KW - Telomerase

KW - Triticum aestivum

UR - http://www.scopus.com/inward/record.url?scp=0033390250&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033390250&partnerID=8YFLogxK

U2 - 10.1007/s004380051150

DO - 10.1007/s004380051150

M3 - Article

C2 - 10628870

AN - SCOPUS:0033390250

VL - 262

SP - 851

EP - 856

JO - Molecular Genetics and Genomics

JF - Molecular Genetics and Genomics

SN - 1617-4615

IS - 4-5

ER -