Euglena gracilis chloroplast ribosomal protein operon: a new chloroplast gene for ribosomal protein L5 and description of a novel organelle intron category designated group III.
We describe the structure (3840 bp) of a novel Euglena gracilis chloroplast ribosomal protein operon that encodes the five genes rpl16-rpl14-rpl5-rps8-rpl36. The gene organization resembles the spc and the 3'-end of the S10 ribosomal protein operons of E. coli. The rpl5 is a new chloroplast gene not previously reported for any chloroplast genome to date and also not described as a nuclear-encoded, chloroplast protein gene. The operon contains at least 7 introns. We present evidence from primer extension analysis of chloroplast RNA for the correct in vivo splicing of five of the introns. Two of the introns within the rps8 gene flank an 8 bp exon, the smallest exon yet characterized in a chloroplast gene. Three introns resemble the classical group II introns of organelle genomes. The remaining 4 introns appear to be unique to the Euglena chloroplast DNA. They are uniform in size (95-109 nt), share common features with each other and are distinct from both group I and group II introns. We designate this new intron category as 'group III'.
Christopher
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DA
Department of Molecular and Cellular Biology, University of Arizona, Tucson 85721.
Hallick
R B
RB
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002736:Chloroplasts / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005056:Euglena gracilis / Q000235:genetics* / Q000378:metabolism; D005091:Exons; D005796:Genes; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009876:Operon; D012313:RNA / Q000235:genetics; D012326:RNA Splicing; D015183:Restriction Mapping; D012269:Ribosomal Proteins / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
D012269:Ribosomal Proteins; C029742:ribosomal protein L5; D012313:RNA; D004247:DNA