Analysis of the human, bovine and rat 33-kDa proteins and cDNA in retina and pineal gland

A monoclonal antibody (mAb) was produced against a bovine retinal 33-kDa protein. Several clones of 33-kDa protein were isolated from each library of cDNA from human, bovine and rat retinas and rat pineal gland by mAb screening and by hybridization with cDNA probes. Each of the four cDNA sequences was determined and amino acid (aa) sequences were deduced from the nucleotide sequences. The latter were nearly identical in rat retina and rat pineal gland (99.6%) and were similar in human, bovine and rat retina (more than 87%). Each of these cDNAs had one long ORF and encoded 245 or 246 aa. The deduced aa sequences in rat retina and rat pineal gland were virtually identical and the sequences in human, bovine and rat retina were highly homologous (more than 88%). The predicted Mr for each of these proteins was 28,246 in the human, 28,176 in bovine, 28,143 in rat retina, and 28,129 in rat pineal gland. Each of the sequences has a putative site for phosphorylation by A kinase; we have confirmed that the putative site is Ser73. These results show that the 33-kDa proteins in the retina and pineal gland have the same sequences and the same phosphorylation site and suggest that the functional role of this protein is the same in the retina and pineal gland.     

Synthesis of an immunopathogenic fusion protein derived from a bovine interphotoreceptor retinoid-binding protein cDNA clone

We have extended the cDNA sequence of bovine interphotoreceptor retinoid-binding protein (IRBP) and subcloned one of the sequenced cDNA fragments into an expression vector. The nucleotide (nt) sequences of four bovine IRBP cDNA clones have been determined. These sequences when assembled cover the 3' proximal 3629 nt of the IRBP mRNA and encode the C-terminal 551 amino acids (aa) of IRBP. This cDNA sequence validates the intron: exon boundaries predicted from the gene. A 2-kb EcoRI insert from lambda IRBP2, one of the clones sequenced, encoding the C-terminal 136 aa of IRBP was subcloned into the expression vector pWR590-1. Escherichia coli carrying this plasmid construction, pXS590-IRBP, produced a fusion protein containing 583 N-terminal aa of beta-galactosidase, three linker aa residues, 136 C-terminal aa of IRBP and possibly a number of additional C-terminal residues due to suppressed termination. This 86-kDa fusion protein, purified by detergent/chaotrope extraction followed by reverse-phase high-performance liquid chromatography, cross-reacted with anti-bovine IRBP on Western blots. This protein induced an experimental autoimmune uveo-retinitis and experimental autoimmune pinealitis in Lewis rats indistinguishable from that induced by authentic bovine IRBP. Thus, it is evident that biological activity of this region of IRBP, as manifested by immuno-pathogenicity, is retained by the fusion protein.     

Carp growth hormone: molecular cloning and sequencing of cDNA

cDNA clones of the fish Cyprinus carpio growth hormone (GH) mRNA have been isolated from a cDNA library prepared from carp pituitary gland poly(A)+RNA. The nucleotide sequence of one of the carp GH cDNA clones containing an insert of 1164 nucleotides (nt) was determined. The cDNA sequence was found to encode a polypeptide of 210 amino acids (aa) including a signal peptide of 22 aa and to contain 5' and 3' untranslated regions of the mRNA of 36 and 498 nt, respectively. The carp GH presents a 63% amino acid sequence homology with the salmon GH, has structural features common with other GH polypeptides of mammalian or avian origin and contains domains of conserved sequence near the N- and C-terminal regions. Southern blot hybridization of carp genomic DNA with GH cDNA probes shows the presence of at least two GH-coding sequences in the fish genome.     

Cloning and characterization of a cDNA encoding bovine mannan-binding protein

To identify the bovine mannan-binding protein (MBP), a search for the cDNA homologue of human MBP was carried out. cDNA clones encoding bovine MBP were isolated from a bovine liver cDNA library using a cDNA fragment encoding a short collagen region, neck domain and carbohydrate recognition domain of human MBP. The cDNA carried an insert of 747 bp encoding a protein of 249 amino acid (aa) residues with a signal peptide of 19 aa. The mannan-binding protein fraction of bovine serum that eluted with 100 mM mannose from a mannan-Sepharose column was analyzed under reducing conditions by SDS-PAGE. The major band of 33 kDa obtained reacted with anti-human MBP rabbit serum. The partial aa sequence of the purified 33-kDa protein was identical to the aa sequence deduced from the obtained cDNA. Results of the passive hemolysis experiment using sheep erythrocytes coated with yeast mannan suggest that this MBP has the ability to activate complement. Northern blot analysis showed a 1.8-kb mRNA that was expressed only in the liver. Based on results of genomic analysis, this bovine MBP is likely to be a homologue of human MBP and to also have homology to rat and mouse MBP-C which are localized in liver cells rather than to rat and mouse MBP-A found in serum. Alignments of bovine collectins show that bovine MBP cannot be included among the other bovine collectins, such as bovine SP-D, conglutinin and CL-43. Finally, these genomic and biological analyses indicate that the cDNA obtained here encoded a bovine serum MBP.     

Cloning and sequencing the cDNA encoding pig liver thioltransferase

We report here, the first successful cloning and sequencing of a full-length cDNA gene (TT) encoding the pig liver thioltransferase (TT). The TT cDNA was obtained by screening a commercial (Clonetech) pig liver cDNA library in lambda gt11, using polyclonal antibodies raised in rabbits against pig liver TT. Two positive clones were identified in 3.5 x 10(5) recombinants. For verification, we successfully hybridized three oligodeoxyribonucleotide nucleotide probes, synthesized according to three different regions of the pig liver TT amino acid (aa) sequence, to both of the positive clones. In addition, the size of the TT beta-galactosidase fusion protein, produced by the positive clone, was consistent with the length of the cDNA. The TT cDNA was subcloned into the EcoRI site of M13mp18 replicative form and sequenced by the dideoxy chain-termination method using 35S-labeled nucleotides. The aa sequence deduced from the cDNA sequence is in exact agreement with the previously reported primary aa sequence, except that the N terminus should be N-acetylalanine followed by glutamine, rather than the reverse, as originally interpreted by conventional mass spectrometry fast atom bombardment analysis of the tryptic peptide corresponding to the first 8 aa residues.     

Bovine corneal protein 54K (BCP54) is a homologue of the tumor-associated (class 3) rat aldehyde dehydrogenase (RATALD)

Amino acid (aa) sequence data from Staphylococcus areas V8 protease-digested bovine corneal 54-kDa protein (BCP54) fragments were utilized to derive mixed oligodeoxyribonucleotide (oligo) primers complementary to the reverse translation products of these sequences. These degenerate oligo primers were used to prime the amplification of BCP54 sequence from bovine corneal epithelial cell cDNA. The cDNA probe generated by this mixed oligo-primed amplification of cDNA was cloned and dideoxy-sequenced. A search of the GenBank database (version 63.0) revealed extensive sequence similarity to the cDNA encoding tumor-associated rat liver (class 3) aldehyde dehydrogenase (RATALD). Nucleotide (nt) and aa sequence alignment of the BCP54 translation product reveals it is 78% and 84% homologous with RATALD at the nt and aa levels, respectively. Conservation of aa sequence elements common to the aldehyde dehydrogenase family thought to be of structural/functional significance is further substantiated by this analysis. Included in the discussion is the likelihood that gene sharing (genes encoding metabolic enzymes and other stable proteins) may extend to the cornea.     

Molecular cloning of a bovine immunoglobulin lambda chain cDNA

A cDNA library of the bovine mammary gland constructed in pBR322 was screened by mRNA hybrid-selected translation and by differential hybridization. Several immunoglobulin (Ig) lambda light-chain clones were identified and sequenced. Nucleotide sequence comparison of bovine and human Ig lambda chains showed a high degree of homology for constant regions and for J regions. The amino acid (aa) sequence encoded by the constant region of the bovine Ig lambda chain cDNA contains 107 aa with differences at 24 aa positions from the human Ig lambda chain. Three complementarity-determining regions (CDR1,2,3) characteristic of the variable region of bovine Ig lambda chain cDNA can be distinguished. The bovine and human sequences display good homology in the framework region 3 (FR3) but only patches of homology throughout the FR2 region. The 5' end of the bovine Ig lambda chain cDNA fragment of clone 1-14E contains five stop codons: two in CDR1, one in FR1 and two in the hydrophobic prepeptide region. These data suggest that the Ig lambda mRNA of clone 1-14E is transcribed from the V lambda pseudogene.     

Molecular cloning and expression in Escherichia coli of the cDNA coding for rat lipocortin I (calpactin II)

Lipocortins (LC) are a family of proteins that were initially described to be induced by glucocorticosteroids and to inhibit phospholipase A2 (PLA2). Using oligodeoxynucleotide probes corresponding to partial amino acid (aa) sequences of rat lipocortin I (LCI), we have isolated a cDNA clone for rat LCI from a cDNA library prepared from poly(A)+RNA of peritoneal cells of dexamethasone-treated rat. The cDNA insert (1355 bp) had an open reading frame of 1038 bp that encoded a 346-aa polypeptide (Mr 38,784). The nucleotide sequence and the amino acid sequence deduced from it showed high homology with the reported sequences of human LCI. A plasmid containing the trc promoter and cDNA sequence for 346 aa residues of the rat LCI was constructed and expressed in Escherichia coli. Antibody to human LCI crossreacted with the recombinant rat LCI, and the recombinant protein had characteristics of natural rat LCI including PLA2 inhibitory activity in vitro.     

Sequence of human eosinophil-derived neurotoxin cDNA: identity of deduced amino acid sequence with human nonsecretory ribonucleases

Several clones of human eosinophil-derived neurotoxin (EDN) cDNA have been isolated from a lambda gt10 cDNA library prepared from mRNA derived from noninduced HL-60 cells. The amino acid (aa) sequence deduced from the coding sequence of the EDN cDNA is identical to the aa sequence of urinary nonsecretory RNase. Comparison of the aa and/or nucleotide (nt) sequences of EDN and other proteins possessing ribonucleolytic activity, namely bovine seminal RNase, human and rat pancreatic RNases, eosinophil cationic protein (ECP), and human angiogenin, shows extensive identity at half-cystine residues and at aa of active sites. Differences in aa sequences at the active sites are often the result of single nt changes in the codons. The data presented here support the concept of a RNase gene superfamily containing secretory and nonsecretory RNases, angiogenin, EDN and ECP.     

Isolation and characterization of two types of cDNA for mitochondrial adenylate kinase and their expression in Escherichia coli

Two cDNA clones for mitochondrial adenylate kinase were isolated from a cDNA library of bovine liver poly(A)+ RNA by using synthetic oligodeoxynucleotides as probes. The clone containing a 0.9-kilobase insert had the reading frame for a 241-residue protein (AK2A), while the other clone containing a 1.6-kilobase insert had the frame for a 234-residue protein (AK2B). Nucleotide sequences of these two clones were the same in the 5' portion up to the coding sequence for the 233rd residue, but different in the remaining 3' portions. The reported amino acid sequence of mitochondrial adenylate kinase from bovine heart corresponded to AK2A. Neither AK2A nor AK2B had a cleavable NH2-terminal presequence as that found in other imported mitochondrial proteins. RNA blot analysis of poly(A)+ RNAs from bovine liver and heart revealed three species of mRNA with approximate sizes of 0.9, 1.4, and 1.7 kilobases. The 1.7- and 1.4-kilobase species were specific for AK2B, whereas the 0.9-kilobase species was specific for AK2A. In the liver, the 1.7-kilobase mRNA was more abundant, whereas in the heart the 0.9-kilobase mRNA was predominant. The 1.4-kilobase mRNA was present only in the heart. The AK2A- and AK2B-coding sequences were expressed in Escherichia coli cells under the control of trc promoter. Both the products reverted the temperature-sensitive phenotype of the adenylate kinase mutant of E. coli.     

Two human genes isolated by a novel method encode DNA-binding proteins containing a common region of homology

Two cDNAs encoding new DNA-binding proteins (Dbps) have been cloned using a human placenta lambda gt11 recombinant cDNA library and DNA fragments as probes. Hybrid proteins expressed by the lambda gt11 cDNA library were blotted onto nitrocellulose filters, and incubated with three different radio-labeled DNA probes containing the human epidermal growth factor (EGF) receptor enhancer or the human c-erbB-2 promoter. Two kinds of clones, named dbpA and dbpB, showed high affinities for the DNA probes. The comparison of the nucleotide and the deduced amino acid (aa) sequences between these two cDNAs indicated that 100 of 109 aa located in the central region of these two Dbps were identical. The dbpA and dbpB-coded proteins also had an affinity for other cDNA probes such as the human c-ski gene, but not for poly(dI-dC).poly(dI-dC), suggesting that the sequence(s) recognized by the dbpA and dbpB-coded proteins may occur frequently, or that these proteins bind to DNA non-specifically in a different manner from that of histones. A simple method, described in this paper, can be used to isolate cDNA clones encoding Dbps. Strategies used for the detection of sequence-specific and non-specific Dbps are discussed.     

cDNA clones encoding bovine gamma-crystallins

We have determined the nucleotide sequence of two bovine lens gamma-crystallin cDNA clones, pBL gamma II-1 and pBL gamma III-1. The 644 bp cDNA insert of pBL gamma II-1 contains coding information for the entire amino acid sequence of bovine gamma II-crystallin. The 497 bp cDNA insert of pBL gamma III-1 encodes a homologous but different gamma-crystallin polypeptide, and appears to lack the coding information for the C-terminal 17 amino acid residues. While the nucleotide and predicted amino acid sequences of the coding regions of the clones show a high degree of homology, the untranslated leader sequences are relatively dissimilar. The leader sequence of pBL gamma III-1 is strikingly homologous to a portion of a rabbit immunoglobulin alpha-heavy chain mRNA.     

Molecular cloning and characterization of cDNA encoding mouse cytokeratin no. 19

We have isolated cDNA clones encoding the mouse cytokeratin No. 19 (Ck 19) from an intestinal cDNA library using synthetic oligodeoxyribonucleotides as probes. We obtained four independent clones, which correspond to about 1.4-kb of ck19 cDNA. Nucleotide sequence analysis revealed that these cDNAs encode a protein of 44,541 Da composed of 403 amino acids (aa). The deduced aa sequence defines an alpha-helical central domain, and suggests that the protein lacks a C-terminal non-alpha-helical tail segment, characteristic of the human and bovine 40-kDa keratins (Ck19). The overall aa identity between mouse Ck19 and human and bovine Ck19 is very high, 82.7% and 82.4%, respectively. The coil-forming central domain of mouse Ck19 has 45-65% similarity to other type-I Ck polypeptides, while it displays only 20-30% similarity to type-II Ck polypeptides. Northern blot analysis showed that mouse ck19 mRNA is strongly expressed in adult intestine, stomach and uterus. Interestingly, it is expressed in a placental cell line and a retinoic acid-treated mouse teratocarcinoma cell line (F9), but not in a parietal yolk sac endoderm-like cell line (PYS-2). This pattern of expression is very similar to that for the mouse gene encoding extra-embryonic endodermal cytoskeletal protein C (EndoC), suggesting they may be the same.     

Nucleotide sequence of a cDNA for the common alpha subunit of the bovine pituitary glycoprotein hormones. Conservation of nucleotides in the 3'-untranslated region of bovine and human pre-alpha subunit mRNAs

A cDNA clone for the pre-alpha subunit of the pituitary glycoprotein hormones has been isolated from a bovine pituitary cDNA library through the use of a pool of synthetic oligodeoxynucleotide probes. This clone, designated pB alpha, contains a 564-base pair insert which includes a portion of the signal sequence, the entire coding sequence of the mature protein, and 224 base pairs of the 3'-untranslated sequence. As expected, the nucleotide and amino acid sequence of the mature bovine alpha subunit was homologous to the sequences reported for humans and rodents, with the most extensive homology occurring between bovine and rodents (85-90%). However, a comparison of the 3'-untranslated regions of pre-alpha subunit mRNA from three different mammalian species indicated that in bovine and rat, or in human and rat, these sequences have rapidly diverged, yielding respective homologies of 21 and 36%. In contrast, the sequence homology observed between the 3'-untranslated regions of bovine and human was 79%, which approaches the level of homology shared by their coding sequences. Thus, the conservation of the 3'-untranslated sequence in bovine and human pre-alpha subunit mRNA may be an indication that this region is functionally significant in these two species.     

Primary structure of bovine lactate dehydrogenase-A isozyme and its synthesis in Escherichia coli

Eleven cDNA clones encoding lactate dehydrogenase(LDH)-A isozyme were isolated from a bovine lymphocyte cDNA library, and the nucleotide sequences of three of the clones (pLDH5, pLDH9 and pLDH12) were determined. With the exception of variation in the 5' portion, two cDNA clones (pLDH9 and pLDH12) appeared to contain the full-length cDNA of 1786 bp, consisting of the protein-coding sequence (996 bp), the 5'- and the 3'-untranslated regions and the poly(dA) tail. The predicted amino acid (aa) sequence of bovine LDH-A (332 aa) showed 96.7% homology with that of pig LDH-A. The protein-coding cDNA region (1650 bp) was inserted into an Escherichia coli expression vector ptac11 and expressed. The protein synthesized in E. coli showed enzyme activity of LDH and was identified by cellogel electrophoresis as LDH-5 isozyme whose subunit M chain is the product of the LDH-A gene.     

Existence of two gamma subunits of the G proteins in brain

Although amino acid sequences have been determined for the alpha and beta subunits of Gs, Gi, and Go, sequences have not been reported for the gamma subunits of these G proteins. In the present paper, we determined the sequences of peptides prepared by partial proteolysis of two different forms of the gamma subunit of Gs, Gi, and Go from bovine brain. Using oligonucleotide probes based on the sequences of two of these peptides, a cDNA clone was isolated from a bovine adrenal cDNA library. This clone contained a 0.9-kilobase cDNA insert that included an open reading frame of 213 bases encoding a 71-amino acid polypeptide with an estimated Mr of 7850. The amino acid sequence predicted for the adrenal cDNA clone was identical to that determined for one form of the gamma subunit from brain. In addition, an antibody to a peptide based on the predicted amino acid sequence of this cDNA clone reacted specifically with one of the brain gamma subunits, indicating the adrenal cDNA clone encodes a gamma subunit present in both adrenal gland and brain. Also, evidence is presented, demonstrating the existence of a second, structurally distinct, form of the gamma subunit of Gs, Gi, and Go in brain.     

Identification of an unusual deletion within homologous repeats of human reticulocyte beta-spectrin and probable peptide polymorphism

We screened two different human reticulocyte cDNA libraries with beta-spectrin(beta Sp)-specific polyclonal antibodies and with our original radiolabeled human BSP cDNA probe (encoding beta Sp). Of the 20 independent clones, the largest had about a 2.5-kb insert corresponding to the deduced amino acid (aa) sequence of the beta-7 to beta-14 repetitive segments. Among these segments, segment 12 was 7 aa shorter than the other repetitive segments. We showed that this truncation was not a result of (i) cloning artifact, (ii) alternate splicing, or (iii) common genomic polymorphism by additional examination of 14 individual human chromosomes. Recently, another laboratory described the BSP nucleotide (nt) sequence overlapping partially with our sequence. These overlapping sequences were homologous with the exception of two nt differences at the positions 1342 and 1514. The discrepancy at nt 1342 changes the His to Arg. This newly derived probe has been used to find an additional example of BSP restriction fragment length polymorphism.     

Cloning of cDNAs encoding human interphotoreceptor retinoid-binding protein (IRBP) and comparison with bovine IRBP sequences

We have determined the sequence of the human interphotoreceptor retinoid-binding protein mRNA from three separately isolated cDNAs. The sequence is 4.28 kb long and encodes a protein of 1247 amino acids (aa) including a putative signal peptide and propeptide. The sequence is shorter (by about 1.67 kb) than the bovine mRNA with the major difference in the lengths located in the 3'-untranslated region. We suggest that this resulted from an insertion in the bovine gene or a large deletion from the human gene. The insertion/deletion is flanked on either side by sequences that are similar in the bovine and human sequences. Like the bovine polypeptide, the deduced protein sequence from the human cDNA contains a fourfold repeat, with each repeat containing about 300 aa. Among the four repeats, the identity is about 30-40%. The identity between the complete bovine and human polypeptide sequences is 84%. The identity between the nucleotide sequences is 83% (excluding the major insertion/deletion). Comparison with the bovine gene indicates that the human sequence may lack about 5-10 bp at the 5' end of the cDNA; it, however, includes a poly(A) tail at the 3' end. Thus, the human sequence is virtually full length, is similar to the bovine sequence, and contains a striking fourfold repeat.