TY - JOUR
T1 - A novel repetitive sequence, termed the JNK repeat family, located on an extra heterochromatic region of chromosome 2R of Japanese rye
AU - Nagaki, Kiyotaka
AU - Tsujimoto, Hisashi
AU - Sasakuma, Tetsuo
N1 - Funding Information:
This work was supported by a research fellowship (No. 5924) of the Japan Society for the Promotion of Science for Young Scientists.
PY - 1999
Y1 - 1999
N2 - Among cultivated rye, Secale cereale L., collected in Japan, we found an extra heterochromatin on the long-arm interstitial region of chromosome 2R. This extra heterochromatin was polymorphic in the population. The plants with the extra heterochromatin showed a specific DNA fragment of 1.2 kb in digests prepared with the restriction enzyme DraI. The fragment was cloned and used as a probe for fluorescent in-situ hybridization (FISH). The clone, pScJNK1, showed a hybridization signal at the extra heterochromatic region. The segregation of the number of signals corresponded to the number of the extra heterochromatin of the 2R chromosome, indicating that the sequence might construct the heterochromatin. Southern hybridization using the clone as a probe showed a ladder pattern, suggesting that the sequence was a tandem repeat. Three sequences homologous to pScJNK1 were isolated; these were 1192-1232 bp, 44.7-45.9% in GC content, highly homologous (> 93%) with each other, and did not show any significant homology to other sequences in a DNA database. Slot blot hybridization using pScJNK1 as a probe indicated that there were about 4000 copies of the sequence in the haploid genome carrying the extra heterochromatin, whereas less than 20 copies existed in the genome without the heterochromatin. Southern hybridization using Msp I and Hap II indicated that all of the second cytosine nucleotides in CCGG sites in the sequence were methylated in the extra heterochromatin.
AB - Among cultivated rye, Secale cereale L., collected in Japan, we found an extra heterochromatin on the long-arm interstitial region of chromosome 2R. This extra heterochromatin was polymorphic in the population. The plants with the extra heterochromatin showed a specific DNA fragment of 1.2 kb in digests prepared with the restriction enzyme DraI. The fragment was cloned and used as a probe for fluorescent in-situ hybridization (FISH). The clone, pScJNK1, showed a hybridization signal at the extra heterochromatic region. The segregation of the number of signals corresponded to the number of the extra heterochromatin of the 2R chromosome, indicating that the sequence might construct the heterochromatin. Southern hybridization using the clone as a probe showed a ladder pattern, suggesting that the sequence was a tandem repeat. Three sequences homologous to pScJNK1 were isolated; these were 1192-1232 bp, 44.7-45.9% in GC content, highly homologous (> 93%) with each other, and did not show any significant homology to other sequences in a DNA database. Slot blot hybridization using pScJNK1 as a probe indicated that there were about 4000 copies of the sequence in the haploid genome carrying the extra heterochromatin, whereas less than 20 copies existed in the genome without the heterochromatin. Southern hybridization using Msp I and Hap II indicated that all of the second cytosine nucleotides in CCGG sites in the sequence were methylated in the extra heterochromatin.
KW - Heterochromatin
KW - Secale cereale L.
KW - Tandem repeat
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U2 - 10.1023/A:1009226612818
DO - 10.1023/A:1009226612818
M3 - Article
C2 - 10328621
AN - SCOPUS:0032905428
VL - 7
SP - 95
EP - 102
JO - Chromosome Research
JF - Chromosome Research
SN - 0967-3849
IS - 2
ER -