A NOVEL TANDEM REPEAT SEQUENCE LOCATED ON HUMAN-CHROMOSOME 4P - ISOLATION AND CHARACTERIZATION

In an effort to analyze the genomic region of the distal half of human chromosome 4p, to where Huntington disease and other diseases have be en mapped, we have isolated the cosmid clone (CRS447) that was likely to contain a region with specific repeat sequences. Clone CRS447 was s ubjected to detailed analysis, including chromosome mapping, restricti on mapping, and DNA sequencing, Chromosome mapping by both a human-CHO hybrid cell panel and FISH revealed that CRS447 was predominantly loc ated in the 4p15.1-15.3 region, CRS447 was shown to consist of tandem repeats of 4,7-kb units present on chromosome 4p, A single EcoRI unit was subcloned (pRS447), and the complete sequence was determined as 47 52 nucleotides. When pRS447 was used as a probe, the number of copies of this repeat per haploid genome was estimated to be 50-70. Sequence analysis revealed that it contained two internal CA repeats and one pu tative ORF. Database search established that this sequence was unrepor ted. However, two homologous STS markers were found in the database. W e concluded that CRS447/pRS447 is a novel tandem repeat sequence that is mainly specific to human chromosome 4p. (C) 1997 Academic Press.