Drosophila RNA polymerase II elongation factor DmS-II has homology to mouse S-II and sequence similarity to yeast PPR2.

DmSII is a Drosophila RNA polymerase II elongation factor which suppresses pausing by RNA polymerase II at specific sites on double stranded templates. Using antibodies produced against the purified protein, a Drosophila cDNA expression library was screened and a cDNA was isolated which encoded a portion of DmSII. When this cDNA was used to probe Kc cell mRNA the predominant species was found to be 1.4 kb in length. The original cDNA was used to screen a Drosophila Kc cell cDNA library resulting in the isolation of a 1.4 kb cDNA which was then sequenced. The deduced protein sequence for DmSII exhibited high similarity to mouse SII protein sequence. In addition, significant sequence similarity was found with the protein encoded by the yeast gene PPR2, which is involved in regulation of URA4 gene expression. The comparison of amino acid sequences suggests that DmSII is comprised of two domains homologous to mouse SII separated by a flexible, serine rich region of low homology. The shorter yeast protein has sequence similarity only to the carboxy terminal domain.     

Cloning of the correct full length cDNA of NF-kappaB-repressing factor

NF-kappaB-repression factor (NRF) is a nuclear inhibitor of NF-kappaB proteins that can silence the IFNbeta promoter. Since NRF was cloned in 1999, in-depth studies have been conducted on the biological functions of this constitutive repressor of NF-kappaB proteins. During large-scale sequencing of a human fetal brain cDNA library we isolated a novel human cDNA that proved to be a correct full-length NRF cDNA. The deduced protein contains 690 aa, and has a G-patch and an R3H domain at its C-terminus. The size of the protein is consistent with its counterparts in mouse and rat. There is considerable evidence that there are some mistakes in the NRF cDNA sequence reported by Nourbakhsh. Here we report the correct, full-length cDNA and protein sequences of NRF. Full-length NRF cDNA is 3247 bp long, contains three exons and maps to human chromosome Xq24. RT-PCR shows that NRF is widely expressed in human tissues.     

The complete primary structure of the human snRNP E protein.

The snRNP E protein is one of four "core" proteins associated with the snRNAs of the U family (U1,U2,U4,U5, and U6). Screening of a human teratoma cDNA library with a partial cDNA for a human autoimmune antigen resulted in the isolation of a cDNA clone containing the entire coding region of this snRNP core protein. Comparison of the 5' end of this cDNA with the sequences of two processed pseudogenes and primer extension data suggest that the cDNA is nearly full length. The longest open reading frame in this clone codes for a basic 92 amino acid protein which is in perfect agreement with amino acid sequence data obtained from purified E protein. The predicted sequence of this protein reveals no extensive similarity to other snRNP proteins, but contains regions of similarity to a eukaryotic ribosomal protein.     

Flotillin 2 is distinct from epidermal surface antigen (ESA) and is associated with filopodia formation.

ECS-1, a monoclonal antibody (MoAb) raised to cultured human keratinocytes, stains the intercellular glycocalyx with a pemphigus-like pattern and recognizes a 35-kDa epidermal surface antigen (ESA) on Western blotting of keratinocyte extracts. When ECS-1 MoAb was used to screen a keratinocyte expression library, a unique cDNA was identified that predicted a 42-kDa globular protein of unknown function. This putative ESA was conserved between mice and humans and was encoded by a gene on chromosome 17q11-12 in linkage with neurofibromin. Homology between the cDNA sequence has been reported with flotillin 1, a caveolae associated protein, as well as Reggie 1 and 2, neuronal proteins expressed during axonal regeneration present in activated GPI-anchored cell adhesion molecules in non-caveolar-associated micropatches. In order to determine whether the cDNA predicted protein and ECS-1 antigen were identical, we compared ECS-1 with the immunoreactivity of a new antibody raised to the cDNA fusion protein in epidermis and cultured cells. The cDNA fusion protein was expressed in bacteria and in cos cells with his, FLAG, and EGFP reporter tags and by stable transfection as an EGFP fusion protein. The fusion protein and native protein of 42 kDa were detected by the new antibody, but not by the original ECS-1. Thus, the ECS-1 antigen, ESA (35 kDa), is clearly distinct from the protein predicted by the cDNA (renamed flotillin 2). Stable transfection of ESA/flotillin 2 fusion protein in cos cells induced filopodia formation and changed epithelial cells to a neuronal appearance. Thus, the function of flotillin 2 may resemble that of the goldfish optic nerve neuronal regeneration proteins, Reggie 1 and 2.     

Characterization of a cDNA encoding rat sterol carrier protein2

Sterol carrier protein2 (SCP2) is a 13.2-kD protein that is thought to be involved in the intracellular transport of cholesterol. Using synthetic oligonucleotides based on the protein sequence of SCP2, a clone (SP43) was isolated from a rat liver cDNA library. The DNA sequence revealed that the cDNA could encode a polypeptide of 273 amino acids (28.9 kD) or 143 amino acids (15.3 kD) in which the carboxy-terminal 123 amino acids are identical to the SCP2 protein. RNA blot hybridization revealed that a variety of rat tissues contain a homologous RNA of a size similar to SP43 (approximately 1.5 kb). Levels of SCP2 mRNA increased in parallel with cytochrome P450scc mRNA in the immature gonadotropin-primed rat ovary. The isolation of a cDNA clone encoding SCP2 will facilitate studies on its role in cholesterol metabolism.     

Correction of the cDNA-derived protein sequence of prostatic spermine binding protein: pivotal role of tandem mass spectrometry in sequence analysis

Spermine binding protein (SBP) is a rat ventral prostate protein that binds various polyamines, and the level of this protein and its mRNA is regulated by androgens. Previously, the cDNA for SBP was cloned and sequenced and an amino acid sequence deduced from the cDNA. Data from cloned and sequenced and an amino acid sequence deduced from the cDNA. Data from partial amino acid sequencing of the purified protein were consistent with the amino acid sequence deduced from the cDNA. However, the amino terminus of the protein was blocked, and therefore, direct protein sequence information confirming the cDNA reading frame of this region could not be obtained by Edman degradation. We have now employed an integrated approach using fast atom bombardment mass spectrometry, tandem mass spectrometry, and conventional sequencing methodologies to establish the amino-terminal sequence of the protein and to identify an amino acid sequence (35 residues) present in the purified protein but missing from the amino acid sequence deduced from cDNA clones for this protein. The missing piece of cDNA corresponds to an exon found in mouse genomic clones for a protein similar to rat SBP. Therefore, the cDNA clones for rat SBP may represent splicing variants that lack the sequence information of one exon. The blocked amino terminus of the protein was identified as 5-oxopyrrolidine-2-carboxylic acid. Mass spectrometry also provided evidence regarding glycosylation of the protein. The first of two potential glycosylation sites clearly carries carbohydrate; the second site is, at most, only partially glycosylated.     

A GAMETOPHYTE CELL WALL PROTEIN OF THE RED ALGA PORPHYRA PURPUREA (RHODOPHYTA) CONTAINS FOUR APPARENT POLYSACCHARIDE-BINDING DOMAINS1

A complementary DNA(cDNA)clone from a Porphyra purpurea (Roth) C. Agardh gametophyte-specific subtracted cDNA library was found to encode a protein containing a signal peptide and four very similar regions with a high degree of amino acid sequence similarity to the cellulose-binding domains of fungal celluloses. Northern hybridization analysis indicated that the messenger RNA of this cDNA is highly abundant in the gametophyte but not detectable in the sporophyte. In vitro translation of the cDNA in the presence of canine pancreatic microsomes demonstrated that the signal peptide is capable of directing the protein into the endoplasmic reticulum where it is glycosylated. Because these observations suggested a possible role as a gametophyte-specific cell wall protein, cell wall protein, were isolated and a major protein having a molecular weight similar to that estimated for the encoded protein was purified. N-terminal sequence analysis indicated that this was the protein encoded by the cDNA. The abundance and organization of this protein suggest a role as a cell wall structural protein involved in cross-linking polysaccharides.     

Molecular cloning, characterization, and expression of a human 14-kDa lectin

Full length cDNAs coding for a 14-kDa beta-galactoside binding lectin have been isolated from HL-60 cells and human placenta. Oligonucleotide probes based on a pentapeptide present in several partial sequences of homologous human lectins were used to screen a lambda GT10 HL-60 cDNA library. The HL-60 cDNA clones that were isolated were used to design a synthetic primer representing the 3'-untranslated region of the HL-60 lectin. This primer was then used to synthesize a lambda GT10 human placenta cDNA library, and restriction fragments of the HL-60 cDNA clones were used to screen the library. The cDNA clones for both HL-60 and placenta lectin had identical sequences with short 5'- and 3'-untranslated regions and coded for a 135-amino acid protein which lacks a hydrophobic signal peptide sequence. Biochemical data show that, despite the presence of a possible N-linked glycosylation site, the protein is not glycosylated. Northern and Southern blot analyses indicate that the 14-kDa lectin is encoded for by a single gene. The lectin cDNA was expressed in Escherichia coli and biologically active protein was purified from cell lysates by affinity chromatography.     

A SPOROPHYTE CELL WALL PROTEIN OF THE RED ALGA PORPHYRA PURPUREA (RHODOPHYTA) IS A NOVEL MEMBER OF THE CHYMOTRYPSIN FAMILY OF SERINE PROTEASES1

A complementary DNA (cDNA) clone from a Porphyra purpurea (Roth) C. Agardh sporophyte-specific subtracted cDNA library was found to encode a protein similar to serine proteases of the chymotrypsin class. The encoded protein contains a typical signal peptide and is particularly similar to chymotrypsins in the regions surrounding the active site residues and the activation site where cleavage of the propeptide occurs. In addition, the six cysteine residues characteristic of chymotrypsins are conserved. However, two of the three residues of the active site His/Asp/Ser charge relay triad have been replaced, indicating that the protein is unlikely to have peptidase activity. Northern hybridization confirmed that this cDNA is derived from an abundant, sporophyte-specific messenger RNA (mRNA). The presence of signal peptide on the encoded protein and the abundance of its mRNA suggested that this protein might be localized in the cell wall. Consequently, sporophyte cell walls were isolated and a major protein having a molecular weight similar to that estimated for the encoded protein was purified. N-terminal sequence analysis indicated that this cell wall protein is identical to that encoded by the cDNA with the amino terminus of the mature protein beginning at the activation site. This cell wall structural protein appears to have evolved from a chymotrypsin-like progenitor but has been adapted to bind cell wall proteins and/or polysaccharides rather than to cleave proteins.     

Identification of a receptor for reg (regenerating gene) protein, a pancreatic beta-cell regeneration factor

Reg (regenerating gene) was isolated as a gene specifically expressed in regenerating islets (Terazono, K., Yamamoto, H., Takasawa, S., Shiga, K., Yonemura, Y., Tochino, Y., and Okamoto, H. (1988) J. Biol. Chem. 263, 2111-2114). Rat and human Reg gene products, Reg/REG proteins, have been demonstrated to stimulate islet beta-cell growth in vitro and in vivo and to ameliorate experimental diabetes. In the present study, we isolated a cDNA for the Reg protein receptor from a rat islet cDNA library. The cDNA encoded a cell surface 919-amino acid protein, and the cells into which the cDNA had been introduced bound Reg protein with high affinity. When the cDNA was introduced into RINm5F cells, a pancreatic beta-cell line that shows Reg-dependent growth, the transformants exhibited significant increases in the incorporation of 5'-bromo-2'-deoxyuridine as well as in the cell numbers in response to Reg protein. A homology search revealed that the cDNA is a homologue to a human multiple exostoses-like gene, the function of which has hitherto been unknown. These results strongly suggest that the receptor is encoded by the exostoses-like gene and mediates a growth signal of Reg protein for beta-cell regeneration.     

Molecular cloning of cDNA for antimycin A-inducible mRNA and its role in cyanide-resistant respiration in Hansenula anomala

A cDNA for mRNA induced by antimycin A in Hansenula anomala was cloned. The mRNA for the cDNA was expressed in the yeast under the conditions expressing the cyanide-resistant respiration activity. The nucleotide sequence revealed a long open reading frame of 342 codons encoding a protein with a molecular weight of 40,282 in the cDNA. An antibody recognizing the protein encoded by the open reading frame was produced. Immunoblotting of H. anomala proteins with this antibody showed that a 36 kDa protein localized in mitochondria was a mature form of the protein encoded by the cDNA. It is suggested that the cloned cDNA encodes a protein involved in the cyanide-resistant respiratory pathway.     

Cloning and characterization of human and rat liver cDNAs coding for a gap junction protein

An extended synthetic oligonucleotide (58-mer) has been used to identify and characterize a human liver gap junction cDNA. The cDNA is 1,574 bases long and contains the entire coding region for a gap junction protein. In vitro translation of the RNA products of this cDNA is consistent with it coding for a 32,022-D protein. Southern blot analysis indicates that the gap junction gene is present as a single copy, and that it can be detected in a variety of organisms using the human liver cDNA as a probe. The human cDNA has been used to screen a rat liver cDNA library, and a rat liver junction cDNA clone has been isolated. The rat liver clone is 1,127 bases in length, and it has strong sequence homology to the human cDNA in the protein-coding region, but less extensive homology in the 3'-untranslated region.     

巴西橡胶树43 kD橡胶粒子膜蛋白基因的cDNA克隆及表达

对43 kD的橡胶粒子膜蛋白进行了分离纯化和其N端氨基酸序列分析,根据N端氨基酸序列,设计一简并引物,通过3'RACE(Rapid Amplification ofcDNA Ends)的方法,获得了43 kD的橡胶粒子膜蛋白的cDNA.该cDNA含有1 385个核苷酸,含有完整的阅读框架,编码381个氨基酸.在终止密码子下游,包含有一个239bp的3'非编码区.该cDNA由5个首尾相连的重复单元组成,每个单元编码76个氨基酸组成的泛素(ubiquitin)单体.编码43 kD橡胶粒子蛋白的基因具有多个拷贝,在胶乳、叶片和树皮都表达.     

Evidence for a second isoform of the catalytic subunit of cAMP-dependent protein kinase

We have used a previously characterized mouse cDNA clone for the catalytic (C) subunit of cAMP-dependent protein kinase (Uhler, M. D., Carmichael, D. F., Lee, D. C., Chrivia, J. C., Krebs, E. G., and McKnight, G. S. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 1300-1304), which we designate C alpha, to isolate cDNA clones coding for a second isoform of the C subunit, C beta. C alpha cDNA clones hybridize to a 2.4-kilobase mRNA on Northern blots whereas C beta cDNA clones detect a 4.3-kilobase mRNA. Nucleotide sequence comparison between C alpha and C beta cDNA clones shows that the C beta cDNA codes for a protein which shows 91% identity with C alpha. Determination of mRNA levels for C beta in various tissues shows that it is most highly expressed in brain although it is detectable in all tissues examined. The presence of two genes coding for the C subunit of cAMP-dependent protein kinase may explain past reports of heterogeneity in C subunit protein preparations.     

Molecular characterization of the interferon-induced 15-kDa protein. Molecular cloning and nucleotide and amino acid sequence

We have isolated a cDNA clone for an interferon-induced 15-kDa protein. The cDNA clone was prepared from mRNA isolated from interferon-beta-treated human Daudi cells. The clone of 635 base pairs contains an open reading frame coding for a protein of 145 amino acids, and suggests for the mRNA a 75-base pair 5' untranslated and a 125-base pair 3' untranslated region. Approximately 85% of the amino acid sequence of the 15-kDa protein has been independently obtained from 2 nmol of material using microsequencing technology on the N terminus of the intact protein and on tryptic and chymotryptic peptides. The amino acid sequence of the isolated protein is identical to the amino acid sequence deduced from the cDNA. Northern blot analysis confirmed that the mRNA for the 15-kDa protein is undetectable in untreated cells, but is greatly induced following interferon treatment.     

Cloning and expression of cDNA coding for bouganin.

Bouganin is a ribosome-inactivating protein that recently was isolated from Bougainvillea spectabilis Willd. In this work, the cloning and expression of the cDNA encoding for bouganin is described. From the cDNA, the amino-acid sequence was deduced, which correlated with the primary sequence data obtained by amino-acid sequencing on the native protein. Bouganin is synthesized as a pro-peptide consisting of 305 amino acids, the first 26 of which act as a leader signal while the 29 C-terminal amino acids are cleaved during processing of the molecule. The mature protein consists of 250 amino acids. Using the cDNA sequence encoding the mature protein of 250 amino acids, a recombinant protein was expressed, purified and characterized. The recombinant molecule had similar activity in a cell-free protein synthesis assay and had comparable toxicity on living cells as compared to the isolated native bouganin.     

The delta-subunit of ATP synthase from bovine heart mitochondria. Complementary DNA sequence of its import precursor cloned with the aid of the polymerase chain reaction.

The delta-subunit of ATP synthase from bovine heart mitochondria is part of the extrinsic membrane domain, F1-ATPase. The mature protein is 146 amino acids in length and its function is obscure. It is encoded by a nuclear gene and is imported into the organelle. Two mixtures of oligonucleotides 17 bases long, designed on the basis of the known protein sequence, have been synthesized and employed as primers on bovine cDNA in the polymerase chain reaction. By this means a segment of bovine cDNA encoding part of the delta-subunit has been amplified, and this DNA segment has been employed to identify related cDNA clones in a library. These clones encode the mitochondrial import precursor of the delta-subunit; the protein sequence of the mature protein deduced from it is exactly the same as that determined earlier by direct sequence analysis. The clones have also been used to show that both the bovine and human genomes seem to contain a single gene for the delta-subunit.