We have studied the structure, genome organization, chromosomal location, conservation across species and transcription on lampbrush chromosomes, of an AT-rich satellite DNA component of the newt, Triturus vulgaris meridionalis. The satellite (Sat G), originally isolated by gradient centrifugation, represents about 2% of the vulgaris genome and comprises a highly repetitive sequence family (HindIII family), whose monomers have been cloned. The repeat units are about 330 bp long, as measured on gels, and a cloned unit (pTvm1) is 310 bp long, as shown by sequencing. Abundant clusters of the HindIII family sequences are located within the pericentric heterochromatin (i.e. the C-bands placed at both sides of, and at a certain distance from, the centromeres) in most chromosomes. Both the sequence family and its overall pattern of chromosomal distribution are conserved within the genus Triturus, despite a few species-specific differences. The great majority of the HindIII family sequences are unexpressed on lampbrush chromosomes; they reside within pericentric, condensed segments of the chromosome axis ("loopless bars"). Only a few sequences are transcribed on some loops, suggesting that transcription promotion does not depend on the satellite sequences themselves.

Heterochromatic DNA in Triturus (Amphibia Urodela). I. A satellite DNA component of the pericentric C-bands

BATISTONI, RENATA;NARDI, IRMA
1986

Abstract

We have studied the structure, genome organization, chromosomal location, conservation across species and transcription on lampbrush chromosomes, of an AT-rich satellite DNA component of the newt, Triturus vulgaris meridionalis. The satellite (Sat G), originally isolated by gradient centrifugation, represents about 2% of the vulgaris genome and comprises a highly repetitive sequence family (HindIII family), whose monomers have been cloned. The repeat units are about 330 bp long, as measured on gels, and a cloned unit (pTvm1) is 310 bp long, as shown by sequencing. Abundant clusters of the HindIII family sequences are located within the pericentric heterochromatin (i.e. the C-bands placed at both sides of, and at a certain distance from, the centromeres) in most chromosomes. Both the sequence family and its overall pattern of chromosomal distribution are conserved within the genus Triturus, despite a few species-specific differences. The great majority of the HindIII family sequences are unexpressed on lampbrush chromosomes; they reside within pericentric, condensed segments of the chromosome axis ("loopless bars"). Only a few sequences are transcribed on some loops, suggesting that transcription promotion does not depend on the satellite sequences themselves.
Barsacchipilone, G; Batistoni, Renata; Andronico, F; Vitelli, L; Nardi, Irma
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/198228
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