Nucleotide sequence of a Drosophila melanogaster cDNA encoding a calnexin homologue

A cDNA which encodes a calnexin (Cnx)-like protein from Drosophila melanogaster has been characterized. The deduced amino acid sequence shares several regions of homology with Cnx from other sources with two conserved motifs each repeated four times. The gene was found to be transcribed in various tissues and at all developmental stages. We have mapped the gene at chromosomal position 99A and we have also mapped the related gene coding for Drosophila calreticulin at 85E.     

Nucleotide sequence of a cDNA clone encoding a Drosophila muscle tropomyosin II isoform

A cDNA clone was sequenced that contains the entire coding region for the muscle tropomyosin II isoform from Drosophila. The cDNA clone is 1253 nucleotides (nt) long and contains an 88-nt 5'-leader sequence and a 310-nt 3'-untranslated sequence. The muscle tropomyosin II isoform consists of 285 amino acids and is 60% homologous with the previously reported muscle tropomyosin I isoform Drosophila and 55% homologous with rabbit muscle tropomyosin.     

Nucleotide sequence and expression of a maize H1 histone cDNA.

The first complete amino acid sequence of a H1 histone of a monocotyledonous plant was deduced from a cDNA isolated from a maize library. The encoded H1 protein is 245 amino acid-long and shows the classical tripartite organization of this class of histones. The central globular region of 76 residues shows 60% sequence homology with H1 proteins from dicots but only 20% with the animal H1 proteins. However, several of the amino acids considered as being important in the structure of the nucleosome are conserved between this protein and its animal counterparts. The N-terminal region contains an equal number of acidic and basic residues which appears as a general feature of plant H1 proteins. The 124 residue long and highly basic C-terminal region contains a 7-fold repeated element KA/PKXA/PAKA/PK. Southern-blot hybridization showed that the H1 protein is encoded by a small multigene family. Highly homologous H1 gene families were also detected in the genomes of several more or less closely related plant species. The general expression pattern of these genes was not significantly different from that of these genes encoding the core-histones neither during germination nor in the different tissues of adult maize.     

Nucleotide sequence and expression of a cDNA encoding chick brain actin depolymerizing factor

Chick brain actin depolymerizing factor (ADF) is a 19-kDa protein that severs actin filaments and binds actin monomers. We have obtained a cDNA encoding ADF by screening a chick embryo lambda gt11 cDNA library with both a rabbit anti-ADF antiserum and two oligonucleotide probes. Several non-full-length clones of 636 bases and one full-length clone of 1886 bases were isolated and sequenced. The full-length cDNA encodes a protein of 165 amino acids with a calculated molecular weight of 18,520. The deduced amino acid sequence shows 73% identity with the porcine brain actin binding protein cofilin. The coding region of the ADF cDNA has been placed in an expression vector, and the resulting protein shows immunoreactivity with an anti-ADF antiserum but not with an anti-cofilin antibody. The expressed ADF has been purified and has an actin depolymerizing activity identical with that of brain ADF. Like cofilin, ADF contains a sequence similar to the nuclear transport signal sequence of the SV40 large T antigen and a calcium/calmodulin-dependent protein kinase II phosphorylation consensus sequence. Northern blots of both embryonic chick brain and muscle RNA revealed two ADF mRNAs of length 2.1 and 0.9 kilobases. Southern blots suggest that the ADF gene is present in a single copy within the chicken genome. ADF contains regions of homology with other actin binding proteins including tropomyosin, gelsolin, and depactin.