Isolation and characterization of a mouse subtelomeric sequence

A mouse subtelomeric sequence, ST1, was generated from genomic DNA of the mouse HR9 (129/Sv origin) cell line by the polymerase chain reaction (PCR) using a single telomeric primer. ST1 was cloned and characterized: it is composed of 670 bp of novel DNA sequence flanked on each end by inverted telomeric hexanucleotide repeats (TTAGGG)n. PCR amplification from BALB/c mouse DNA using this single primer gave the same major product. Southern analysis and PCR using internal ST1 primers confirmed that the ST1 sequence is present in mouse genomic DNA. In situ hybridization to metaphase chromosomes of SJL origin mapped ST1 to many, if not every, mouse telomere. PCR experiments using different combinations of the telomeric, minor satellite, and ST1 primers indicated that some ST1 copies are adjacent to minor satellite sequences, that telomeric and ST1 sequences are not generally interspersed with minor satellite sequences, and that ST1 and the minor satellite have a consistent and specific orientation relative to each other and to the telomere.