Genes coding for the elongation factor EF‐1α in Artemia

Abstract

The elongation factor EF‐1α is one of the most abundant proteins in eukaryotic cells, where it catalyzes the binding of aminoacyl‐tRNA to ribosomes. The genes coding for this protein in the brine shrimp Artemia were analyzed by gene cloning, electron microscopy and chromosomal blot hybridization. There are only a few (about four) copies of one type of gene per haploid genome. These genes contain five exons divided over 104 base pairs. Local rearrangements give rise to a number of gene variants. Cross‐hybridizations of Artemia cDNA probes with yeast and Drosophila DNA revealed two different yeast EF‐1α genes and one or two different Drosophila genes, respectively. Nucleotide sequencing revealed signals for synthesis and processing of EF‐1α transcripts as well as the exact location of exons. One interruption in the coding sequence corresponds closely to a splice junction in the gene coding for the homologous chloroplast protein EF‐Tu from Euglena gracilis, presumably of prokaryotic origin. The first exon in the chloroplast gene codes for the region of EF‐Tu that is homologous to regions of the elongation factor EF‐G and of the initiation factor IF2, respectively. Copyright © 1986, Wiley Blackwell. All rights reserved