8 research outputs found
The Mitochondrial Genome of the Peronosporomycete Saprolegnia Ferax: Organization, Gene Content, and Nucleotide Sequence
The mitochondrial genome of the peronosporomycete
water mold Saprolegnia ferax has been
characterized as a 46 930 bp circle containing an
8618 bp large inverted repeat (LIR). Eighteen reading
frames encode identified subunits of respiratory
complexes I, III, IV and V; 16 encode polypeptides
of small and large mitoribosome subunits; and one
encodes a subunit of the sec-independent protein
translocation pathway. Of four additional putative
reading frames three are homologues of those found
in the related Phytophthora infestans genome. Protein
encoding loci in the tightly compacted genome typically
are arranged in operon-like clusters including
three abutting and two overlapping pairs of reading
frames. Translational RNAs include the mitochondrial
small and large subunit rRNAs and 25 tRNA species.
No tRNAs are encoded to enable translation of
any threonine or the arginine CGR codons. The LIR
separates the molecule into 19 274 bp large and
10 420 bp small single copy regions, and it encodes
intact duplicate copies of four reading frames encoding
known proteins, both rRNAs, and five tRNAs. Partial
39 sequences of three additional reading frames
are duplicated at single copy sequence junctions. Active
recombination between LIR elements generates
two distinctive gene orders and uses the duplicated
39 sequences to maintain intact copies of the partially
duplicated loci.
Key words: mitochondria