Pericentromeric regions containing 1.688 satellite DNA sequences show anti-kinetochore antibody staining in prometaphase
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O R I GI N A L P A P E R
J. P. Abad á M. Agudo á I. Molina á A. Losada P. Ripoll á A. Villasante
Pericentromeric regions containing 1.688 satellite DNA sequences show anti-kinetochore antibody staining in prometaphase chromosomes of Drosophila melanogaster Received: 23 May 2000 / Accepted: 20 July 2000 / Published online: 5 September 2000 Ó Springer-Verlag 2000
Abstract A striking characteristic of the centromeric heterochromatin of Drosophila melanogaster is that each chromosome carries dierent satellite DNA sequences. Here we show that while the major component of the 1.688 satellite DNA family expands across the centromere of the X chromosome the rest of the minor variants are located at pericentromeric positions in the large autosomes. Immunostaining of prometaphase chromosomes with the kinetocore-speci®c anti-BUB1 antibody reveals the transient presence of this centromeric protein in all the regions containing the 1.688 satellite. Key words Satellite DNA á Centromeric heterochomatin á Drosophila melanogaster
Introduction The centromere is the chromosomal region that interacts with the spindle microtubules to ensure chromatid segregation during mitosis. Although, paradoxically, the centromeric sequences do not seem to be broadly conserved throughout evolution, it remains possible that a detailed comparison of these sequences will permit the identi®cation of a common centromeric structural motif (Abad and Villasante 2000). Moreover,
Communicated by D. Gubb J. P. Abad á M. Agudo á I. Molina A. Losada1 á P. Ripoll á A. Villasante (&) Centro de BiologõÂ a Molecular ``Severo Ochoa'' (CSIC-UAM), 28049 Madrid, Spain E-mail: [email protected] Tel.: +34-913-974692 Fax: +34-913-974799 Present address: Cold Spring Harbor Laboratory, P.O. Box 100, Cold Spring Harbor, NY 11724, USA 1
The ®rst two authors contributed equally to this work
exceptional instances of centromere activity associated with non-centromeric DNA (du Sart et al. 1997; Williams et al. 1998) and the existence of centromere inactivation/activation (Steiner and Clarke 1994; Fisher et al. 1997; Sullivan and Willard 1998; Agudo et al. 2000) show that epigenetic factors play a role in centromere function. The centromeres of Drosophila melanogaster have been de®ned using chromosome rearrangements (Gatti and Pimpinelli 1983, 1992; Dimitri 1991). In this ¯y, each centromeric region seems to contain dierent repeated DNA sequences (Abad et al. 1992; Lohe et al. 1993; Pimpinelli et al. 1995; Sun et al. 1997; Agudo et al. 1999). Therefore, this species can be used as a model system for studying how dierent sequences are able to form a centromere. With this aim, we have been studying the 1.688 satellite DNA family (Carlson and Brutlag 1977; Hsieh and Brutlag 1979; Lohe and Brutlag 1986; Losada and Villasante 1996) because the major component of this complex satellite, the 359-bp repeats, extends across the cytologically de®ned centromere of the normal X chromosome (Lohe et al. 1993). The existence of pericentric inversions such as In(1LR)scV1 (see Lindsle
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