Molecular anatomy of a small chromosome in the green alga Chlorella vulgaris.
A contig covering the entire region of Chlorella vulgaris chromosome I (980 kb long), consisting of 33 cosmid clones has been constructed. By cross-hybridization with other chromosomal DNAs, universal structural elements were detected and localized on the contig. They were composed of at least three different elements: short interspersed DNA elements (SINE)-like elements, long interspersed DNA elements (LINE)-like elements and a putative centromere-like element. At least 36 copies of SINE-like elements were distributed over chromosome I with preferential locations on the right half of the chromosome. DNA fragments containing a SINE-like sequence showed a bent or curved DNA nature on polyacrylamide gel electrophoresis. LINE-like elements were clustered at the left terminus of chromosome I where they formed a tandem array of six copies immediately adjacent to the telomeric repeats. A long sequence element localized at a unique region of chromosome I also existed in a single copy on each chromosome and contained a sequence related to the reverse transcriptase domain of retrotransposons. This feature was compared with the reported centromere-associated elements of higher plants. With its comparative simplicity, the organization of Chlorella chromosome I genomic elements may serve as a prototypic experimental system for deciphering the complexity of huge plant chromosomes.
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan.
Y
Y
Noutoshi
Y
Y
Ito
S
S
Kanetani
M
M
Fujie
S
S
Usami
T
T
Yamada
D001483:Base Sequence; D002503:Centromere / Q000235:genetics; D002708:Chlorella / Q000235:genetics*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003360:Cosmids; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D018626:Retroelements / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D016615:Telomere / Q000235:genetics
D018626:Retroelements