A chromosome 13-specific human satellite I DNA subfamily with minor presence on chromosome 21: further studies on Robertsonian translocations.
We describe a new human satellite I DNA subfamily (pTRI-6) which is composed of 72 copies of monomeric repeating units of 42 basepairs (bp). These repeating units are tandemly organized into a higher order structure of 2.97 kilobases (kb). Sequencing of this DNA revealed base substitutions, deletions and insertions, and an overall conservation of 85% among the monomers. The sequence has a high AT content of 77%. Under low-stringency in situ hybridization conditions, satellite I is found on the pericentric regions of chromosomes 3 and 4 and on all the acrocentric chromosomes. On the acrocentric chromosomes, satellite I is further detected on the distal p13 region. Analysis of somatic cell hybrids under high stringency indicates the presence of the pTRI-6 subfamily predominantly on chromosome 13. Chromosome 21 shows a 50- to 100-fold reduced amount of this subfamily and the presence of other sequences closely related to pTRI-6. Investigation of a group of 11 human t(14q21q) Robertsonian translocations revealed the retention of satellite I DNA around the breakpoints in all cases. These results extend our understanding of these translocations and of the general structural organization of the cen-pter regions of the acrocentric chromosomes.
Kalitsis
P
P
Murdoch Institute for Research into Birth Defects, Royal Children's Hospital, Melbourne, Victoria, Australia.
Earle
E
E
Vissel
B
B
Shaffer
L G
LG
Choo
K H
KH
D001483:Base Sequence; D002882:Chromosomes, Human, Pair 13; D002886:Chromosomes, Human, Pair 17; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004247:DNA / Q000235:genetics; D004276:DNA, Satellite / Q000235:genetics*; D005260:Female; D006801:Humans; D006822:Hybrid Cells; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D014178:Translocation, Genetic
D004276:DNA, Satellite; D004247:DNA