Molecular organization and chromosomal location of human GC-rich heterochromatic blocks

Raffaella Meneveri, Alessandra Agresti, Anna Marozzi, Salvatore Saccone, Mariano Rocchi, Nicoletta Archidiacono, Gianmarco Corneo, Giuliano Delia Valle, Enrico Ginelli

Research output: Contribution to journalArticlepeer-review


From the sequencing of three genomic DNA fragments and PCR amplification products from total human DNA, we have derived the sequence of a 545-bp Sau3A fragment (68% GC), representative of a family of human DNA repeats. Since previous studies suggested its linkage with unrelated Sau3A repeats of 68 bp (54% GC) (β-satellite sequences), this feature was further investigated by in situ hybridization experiments and by Southern blot analysis of a panel of DNAs from human-Chinese hamster somatic cell hybrids. Both DNA repeats are preferentially localized on the heterochromatic regions of acrocentric chromosomes, on the pericentromeric heterochromatin of chromosome 1, 3 and 9, and on the proximal euchromatic region of the chromosome Y q arm. On chromosome 9, both repeats are part of a 2.7-kb higher-order repeat unit. These results and the Southern blot analysis on partial digests of total DNA, suggest that the linkage between the two repetitive DNA sequences is a constant feature throughout the genome. Furthermore, Southern blot analysis of HpaII-digested and MspI-digested DNA from different human tissues and tumor cell lines indicates that the investigated heterochromatic blocks appear to be subjected to changes in their methylation pattern.

Original languageEnglish
Pages (from-to)227-234
Number of pages8
Issue number2
Publication statusPublished - Jan 30 1993


  • human/hamster hybrids
  • in situ hybridization
  • methylation
  • Recombinant DNA
  • repetitive DNA sequences
  • β-satellite sequences

ASJC Scopus subject areas

  • Genetics


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