ISOLATION AND CHARACTERIZATION OF 5 RICE TELOMERE-ASSOCIATED SEQUENCES

According to the telomere-repeated sequences of rice, two primers: (TT TAGGG)(3) and (CCCTAAA)(3)CCC were used to amplify rice telomere-assoc iated sequences (TASs). For PCR template preparation, total DNA was di gested with restrictive endonuclease and then ligated. Using the ligat es or total DNA as template, eight fragments were obtained with the si ngle primer by the PCR reaction. To confirm that the sequences are der ived from telomeric DNA, we conducted Bal31 digestion analysis. Of the eight fragments, seven were susceptible to Bal31 treatment, suggestin g that they were TASs. These DNA fragments were further demonstrated t o be rice sub-telomeric sequences by RFLP mapping. Five sequences have been mapped to the distal ends on rice chromosome 5, 6, 7 and 9, and two other sequences have been mapped at interstitial sites, suggesting that (TTTAGGG), also exist in the middle of rice chromosomes. All eig ht fragments were sequenced and characterized.