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Macronuclear and micronuclear configurations of a gene encoding the protein synthesis elongation factor EF 1α in Stylonychia lemnae
Author(s) -
Bierbaum P.,
Dönhoff T.,
Klein A.
Publication year - 1991
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1991.tb00804.x
Subject(s) - biology , gene , genetics , coding region , intron , elongation factor , stop codon , microbiology and biotechnology , rna , ribosome
Summary The micronuclear and macronuclear configurations of a gene encoding the protein synthesis elongation factor EF 1α in the hypotrich ciliate Stylonychia lemnae were compared. The two sequences are generally colinear. The coding sequence of the micronuclear gene is, however, interrupted by a 64 bp insert flanked by a 2 bp direct repeat in a gene region which is moderately conserved among EF 1α genes of different organisms. The insertion site is distinct from known intron positions in eukaryotic EF 1α genes. The insert sequence shows inverted repeats at its ends and thus exhibits typical features of an internal eliminated sequence (IES). Comparison with other such sequences in the related organism Oyxtricha nova shows that the IES falls into a new group of such elements. The macronuclear gene exhibits a strikingly limited codon usage, which cannot be simply explained by the overall base composition of the DNA but probably also relates to the very high copy number of the macronuclear gene and the putative high amount of the gene product.