High frequency intragenic recombination during macronuclear development in Tetrahymena thermophila restores the wild-type SerH1 gene.
Macronuclear development in ciliates is characterized by extensive rearrangement of genetic material, including sequence elimination, chromosome fragmentation and telomere addition. Intragenic recombination is a relatively rare, but evolutionarily important phenomenon occurring in mitosis and meiosis in a wide variety of organisms. Here, we show that high frequency intragenic recombination, on the order of 30%, occurs in the developing amitotic macronucleus of the ciliate Tetrahymena thermophila. Such recombination, occurring between two nonsense transition mutations separated by 726 nucleotides, reproducibly restores wild-type expression of the SerH1 surface protein gene, thus mimicking complementation in trans heterozygotes. Recombination must be considered a potentially important aspect of macronuclear development, producing gene combinations not present in the germinal micronucleus.
Deak
J C
JC
Department of Biology, Cleveland State University, Ohio 44115, USA.
Doerder
F P
FP
D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics*; D000954:Antigens, Surface / Q000235:genetics*; D002467:Cell Nucleus; D015870:Gene Expression; D017125:Genes, Protozoan; D015800:Protozoan Proteins; D011995:Recombination, Genetic; D016808:Tetrahymena thermophila / Q000235:genetics*
D000953:Antigens, Protozoan; D000954:Antigens, Surface; D015800:Protozoan Proteins; C043323:immobilization antigens