Molecular Structure of a Functional Drosophila Centromere

Abstract

Centromeres play a critical role in chromosome inheritance but are among the most difficult genomic components to analyze in multicellular eukaryotes. Here, we present a highly detailed molecular structure of a functional centromere in a multicellular organism. The centromere of the Drosophila minichromosome Dp1187 is contained within a 420 kb region of centric heterochromatin. We have used a new approach to characterize the detailed structure of this centromere and found that it is primarily composed of satellites and single, complete transposable elements. In the rest of the Drosophila genome, these satellites and transposable elements are neither unique to the centromeres nor present at all centromeres. We discuss the impact of these results on our understanding of heterochromatin structure and on the determinants of centromere identity and function.

Satellite DNA in insects: a review

“…D. melanogaster transposon BEL has been found in the functional 420-kb Drosophila minichromosome centromere. The transposon BEL is one of the five conserved, intact and complete transposons inserted directly into the AATAT array of this functional centromere (Sun et al, 1997). The fly C. capitata also showed interspersed TEs in satDNA (Stratikopoulos et al, 2002), some of which was highly conserved and showed a significant similarity with transposon BEL.…”

“…The fly C. capitata also showed interspersed TEs in satDNA (Stratikopoulos et al, 2002), some of which was highly conserved and showed a significant similarity with transposon BEL. However, it is not known whether this conservation, even in different organisms, is due to a recent insertion or it is a consequence of a selective or functional constraint probably related to centromere activity (Sun et al, 1997;Stratikopoulos et al, 2002).…”

A Molecular-Cytogenetic Method for Locating Genes to Pericentromeric Regions Facilitates a Genomewide Comparison of Synteny Between the Centromeric Regions of Wheat and Rice

“…Centromeric satellites serve as the core of the centromere, which is flanked by pericentric heterochromatin rich in middle repetitive elements, including retroelements and transposons. Because of the abundance of various repeats, centromeres of most eukaryotic chromosomes are upward of 1 Mb in size, mostly devoid of genes, and their sequencing and assembly pose a big challenge (Su et al 1997;Hosouchi et al 2002). Among the sequenced genomes of many multicellular eukaryotes, including Drosophila melanogaster, human, mouse, Arabidopsis thaliana, and rice, only the centromeres of rice chromosomes 3, 4, 5, and 8 have been fully assembled Wu et al 2004;Y.…”

Transcription of the 1.688 Satellite DNA Family Is Under the Control of RNA Interference Machinery inDrosophila melanogasterOvaries

“…In the Drosophila melanogaster genome, each centromeric region seems to contain different sets of satellite DNA sequences (Abad et al 1992(Abad et al , 2000Lohe et al 1993;Sun et al 1997;Agudo et al 1999;Lamb and Birchler 2003). The X chromosome contains a large block of complex 1.688 satellite DNA (359-bp repeat unit), located in the centromeric region and in the adjacent 1 pericentromeric heterochromatin (Lohe et al 1993;Abad et al 2000) (Figure 1A), and large autosomes contain arrays of different subfamilies of 1.688 satellite DNA in the pericentromeric heterochromatin.…”