Cloning and analysis of cDNA sequences coding for two 16 kllodalton heat shock proteins (hsps) in Caenorhabditis elegans: homology with the small hsps of Drosophila

摘要

The nucleotide sequences of two different cDNAs, CEHS48 and CEHS41, coding for the 16,000 dalton heat shock proteins (hsps) of Caenorhabditis elegans have been determined. CEHS48 codes for a polypeptide of 135 amino acids, approximately 15 fewer than the complete protein while CEHS41 is missing approximately 46 amino acids. From nucleotide 113 to the TAA termination signal the extent of homology between the sequences is 91% Toward the 5' ends, the homology drops to 20Z and results in completely divergent amino acid sequences. The 3' noncoding regions are only 30Z homologous. Only CEHS48 contains a poly(A) signal and a poly(A) tail, suggesting that CEHS41 has an incomplete 3' end. The region from amino acid 43 to amino acid 115 shows extensive homology with corresponding regions in the four small hsps of Drosophila melanogaeter and in mammalian a-crystallin. Two-dimensional gel analysis of Jji vitro synthesized hspl6 reveals the existence of five distinct components of identical molecular weights, but with different isoelectric points