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Molecular and General Genetics MGG

, Volume 246, Issue 1, pp 29–36 | Cite as

Molecular organization of Chlorella vulgaris chromosome I: presence of telomeric repeats that are conserved in higher plants

  • Takanobu Higashiyama
  • Sinya Maki
  • Takashi Yamada
Original Paper

Abstract

The unicellular green alga Chlorella vulgaris (strain C-169) has a small genome (38.8 Mb) consisting of 16 chromosomes, which can be easily separated by CHEF gel electrophoresis. We have isolated and characterized the smallest chromosome (chromosome 1, 980 kb) to elucidate the fundamental molecular organization of a plant-type chromosome. Restriction mapping and sequence analyses revealed that the telomeres of this chromosome consist of 5′-TTTAGGG repeats running from the centromere towards the termini; this sequence is identical to those reported for several higher plants. This sequence is reiterated approximately 70 times at both termini, although individual clones exhibited microheterogeneity in both sequence and copy number of the repeats. Subtelomeric sequences proximal to the termini were totally different from each other: on the left arm, unique sequence elements (14–20 bp) which were specific to chromosome I, form a repeat array of 1.7 kb, whereas a 1.0 kb sequence on the right arm contained a poly(A)-associated element immediately next to the telomeric repeats. This element is repeated several times on chromosome I and many times on all the other chromosomes of this organism.

Key words

Chlorella vulgaris Small-sized chromosomes Pulsed field gel electrophoresis Physical mapping Telomeric repeats 

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Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Takanobu Higashiyama
    • 1
  • Sinya Maki
    • 1
  • Takashi Yamada
    • 1
  1. 1.Department of Fermentation TechnologyFaculty of Engineering, Hiroshima UniversityHigashi-Hiroshima 724Japan

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