Sequence and structure of the extrachromosomal palindrome encoding the ribosomal RNA genes in Dictyostelium

被引：37

作者：

Sucgang, R

Chen, GK

Liu, W

Lindsay, R

Lu, J

Muzny, D

Shaulsky, G

Loomis, W

Gibbs, R

Kuspa, A ^{[1
]}

机构：

[1] Baylor Coll Med, Dept Biochem & Mol Biol, Houston, TX 77030 USA

[2] Baylor Coll Med, Human Genome Sequencing Ctr, Houston, TX 77030 USA

[3] Baylor Coll Med, Dept Human & Mol Genet, Houston, TX 77030 USA

[4] Univ Calif San Diego, Div Biol, Sect Cell & Dev Biol, La Jolla, CA 92093 USA

来源：

NUCLEIC ACIDS RESEARCH | 2003年 / 31卷 / 09期

关键词：

D O I：

10.1093/nar/gkg348

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Ribosomal RNAs (rRNAs) are encoded by multicopy families of identical genes. In Dictyostelium and other protists, the rDNA is carried on extrachromosomal palindromic elements that comprise up to 20% of the nuclear DNA. We present the sequence of the 88 kb Dictyostelium rDNA element, noting that the rRNA genes are likely to be the only transcribed regions. By interrogating a library of ordered YAC clones, we provide evidence for a chromosomal copy of the rDNA on chromosome 4. This locus may provide master copies for the stable transmission of the extrachromosomal elements. The extrachromosomal elements were also found to form chromosome-sized clusters of DNA within nuclei of nocodazole-treated cells arrested in mitosis. These clusters resemble true chromosomes and may allow the efficient segregation of the rDNA during mitosis. These rDNA clusters may also explain the cytological observations of a seventh chromosome in this organism.

引用

页码：2361 / 2368

页数：8

共 44 条

[41] HUMAN RIBOSOMAL-RNA GENES - ORIENTATION OF THE TANDEM ARRAY AND CONSERVATION OF THE 5' END [J].