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W J Rutter

Publications and source records attributed to W J Rutter.

At least 163 records · Page 9Linked to original sources
PubMed1983

Polymorphic human somatostatin gene is located on chromosome 3.

Somatostatin is a 14-amino-acid neuropeptide and hormone that inhibits the secretion of several peptide hormones. The human gene for somatostatin SST has been cloned, and the sequence has been determined. This clone was used as a probe in chromosome mapping studies to detect the human somatostatin sequence in human-rodent hybrids. Southern blot analysis of 41 hybrids, including some containing translocations of human chromosomes, placed SST in the q21 leads to qter region of chromosome 3. Human DNAs from unrelated individuals were screened for restriction fragment polymorphisms detectable by the somatostatin gene probe. Two polymorphisms were found: (i) an EcoRI variant located at the 3' end of the gene, found in Caucasian, U.S. Black, and Asian populations with a frequency of approximately 0.10 and (ii) a BamHI variant in the intron, which occurs in Caucasians at a frequency of 0.13.

Animals↗
PubMed1983

Synthesis of hepatitis B surface antigen in mammalian cells: expression of the entire gene and the coding region.

We have constructed two simian virus 40 early replacement recombinants that have the coding sequences for hepatitis B virus surface antigen (HBsAg). One construction, LSV-HBsAg, has the coding region for HBsAg but not the portion encoding the putative pre-surface antigen leader. Transformed monkey kidney cells (COS) infected with this recombinant express large quantities of the characteristic partially glycosylated HBsAg molecule, which are assembled into 22-nm particles that appear similar to those produced by human liver cells infected with hepatitis B virus. This result indicates that the pre-surface antigen sequences are not required for the synthesis of HBsAg or its assembly into particulate structures. The second recombinant, LSV-HBpresAg, has the entire surface antigen gene, including the putative promoter and pre-surface antigen region. COS cells infected with this recombinant plasmid produce 40- to 50-fold less HBsAg than those infected with the LSV-HBsAg recombinant plasmid. RNA mapping studies suggest that the transcription of the HBsAg gene is initiated at more than one site, or alternatively, that RNA splicing of transcripts occurs in the pre-surface antigen region.

Animals↗
PubMed1983

Transcription of hepatitis B virus by RNA polymerase II.

We employed an in vitro cell-free transcription system to locate RNA polymerase II promoters on the hepatitis B virus genome. The strongest promoter precedes the surface antigen (HBsAg) gene, which is comprised of a long (500 base pairs) presurface region as well as the mature HBsAg coding sequence. The origin of this transcript was localized by using truncated templates and S1 endonuclease mapping. The activity of the promoter was confirmed in transfection experiments in which the complete HBsAg gene was introduced into monkey kidney cells via a simian virus 40 expression vector. A second RNA polymerase II promoter preceding the HBcAg gene was also active in the cell-free system. The presence of multiple promoters in the hepatitis B virus genome suggests that the relative levels of viral-specific proteins detected in liver and serum may reflect differential or regulated promoter efficiency.

Base Sequence↗
PubMed1983

Hepatitis B virus encodes an RNA polymerase III transcript.

We demonstrated that cloned hepatitis B virus (HBV) DNA directs the synthesis of a 700-base RNA (HBV 700) by RNA polymerase III in a cell-free transcription system. HBV 700 is the only transcript known to originate from the viral short strand and has been mapped to the region between roughly 1,635 and 954 base pairs on the viral map, between the surface and core antigen coding sequences but overlapping and opposing the putative DNA polymerase and B protein genes. The in vitro initiation sites for the HBV 700 and core antigen RNAs are only 50 bases apart, suggesting that these two genes may be coordinately regulated. Moreover, both of these initiation sites appear to lie within the approximately 300-base double-stranded region (the nick region) between the 5' end of the HBV short strand and the nick in the viral long strand. We found two unusual sequence elements in the nick region that are conserved between the human and woodchuck viruses.

DNA, Viral↗
PubMed1982

Intron-exon splice junctions map at protein surfaces.

There have been several suggested explanations for the presence of noncoding intervening sequences in many eukaryotic structural genes. They may be examples of 'selfish DNA, conferring little phenotypic advantage, or they may have some importance in gene expression and/or evolution. It has been suggested that each exon (coding sequence) may represent a structural or functional unit of the encoded protein, for which there is good evidence in the case of immunoglobulin and haemoglobin genes. Exon modification, duplication and recombination may thus be general mechanisms for the rapid evolution of eukaryotic structural genes. In many cases, however, it is not apparent that an exon corresponds to some specific feature of the encoded protein. We describe here evidence that intron-exon junctions usually map to amino acid residues located at the protein surface, suggesting a restriction on the permitted positions of introns within a gene.

Amino Acids↗
PubMed1982

Synthesis and assembly of hepatitis B virus surface antigen particles in yeast.

The surface antigens of hepatitis B virus (HBsAg) has been synthesized in the yeast Saccharomyces cerevisiae by using an expression vector that employs the 5'-flanking region of yeast alcohol dehydrogenase I as a promotor to transcribe surface antigen coding sequences. The protein synthesized in yeast is assembled into particles having properties similar to the 22-nm particles secreted by human cells.

Alcohol Dehydrogenase↗
PubMed1982

Primary structure of two distinct rat pancreatic preproelastases determined by sequence analysis of the complete cloned messenger ribonucleic acid sequences.

The mRNA sequences for two rat pancreatic elastolytic enzymes have been cloned by recombinant DNA technology and their nucleotide sequences determined. Rat elastase I mRNA is 1113 nucleotides in length, plus a poly(A) tail, and encodes a preproelastase of 266 amino acids. The amino acid sequence of the predicted active form of rat elastase I is 84% homologous to porcine elastase 1. Key amino acid residues involved in determining substrate specificity of porcine elastase 1 are retained in the rat enzyme. The activation peptide of the zymogen does not appear related to that of other mammalian pancreatic serine proteases. The mRNA for elastase I is localized in the rough endoplasmic reticulum of acinar cells, as expected for the site of synthesis of an exocrine secretory enzyme. Rat elastase II mRNA is 910 nucleotides in length, plus a poly(A) tail, and encodes a preproenzyme of 271 amino acids. The amino acid sequence is more closely related to porcine elastase 1 (58% sequence identity) than to the other pancreatic serine proteases (33-39% sequence identity). Predictions of substrate preference based upon key amino acid residues that define the substrate binding cleft are consistent with the broad specificity observed for mammalian pancreatic elastase 2. The activation peptide is similar to that of the chymotrypsinogens and retains an N-terminal cysteine available to form a disulfide link to an internal conserved cysteine residue.

Amino Acid Sequence↗
PubMed1982

Rat preprocarboxypeptidase A: cDNA sequence and preliminary characterization of the gene.

Rat carboxypeptidase A cDNA clones have been isolated from a cDNA library prepared from pancreatic mRNA. An almost complete mRNA sequence has been deduced that predicts a polypeptide having 78% amino acid sequence homology with bovine carboxypeptidase A. The amino acid sequence of the activation and signal peptides of the carboxypeptidase A precursor were inferred from the nucleotide sequence. The cDNA was used as a probe to identify DNA fragments containing carboxypeptidase A sequences in a bacteriophage lambda library of rat genomic DNA. Heteroduplexes revealed that the DNA coding sequence occupies 5.5 kilobases and is interrupted by nine intervening sequences. The nucleotide sequence of the 5' end of the gene and the adjacent flanking region provides information on the site of initiation of transcription and the putative control regions. There is no evident relationship between the localization of intervening sequences in the gene and functional/structural domains of the protein.

Animals↗
PubMed1982

Human somatostatin I: sequence of the cDNA.

RNA has been isolated from a human pancreatic somatostatinoma and used to prepare a cDNA library. After prescreening, clones containing somatostatin I sequences were identified by hybridization with an anglerfish somatostatin I-cloned cDNA probe. From the nucleotide sequence of two of these clones, we have deduced an essentially full-length mRNA sequence, including the preprosomatostatin coding region, 105 nucleotides from the 5' untranslated region and the complete 150-nucleotide 3' untranslated region. The coding region predicts a 116-amino acid precursor protein (Mr, 12.727) that contains somatostatin-14 and -28 at its COOH terminus. The predicted amino acid sequence of human somatostatin-28 is identical to that of somatostatin-28 isolated from the porcine and ovine species. A comparison of the amino acid sequences of human and anglerfish preprosomatostatin I indicated that the COOH-terminal region encoding somatostatin-14 and the adjacent 6 amino acids are highly conserved, whereas the remainder of the molecule, including the signal peptide region, is more divergent. However, many of the amino acid differences found in the pro region of the human and anglerfish proteins are conservative changes. This suggests that the propeptides have a similar secondary structure, which in turn may imply a biological function for this region of the molecule.

Amino Acid Sequence↗
PubMed1982

Hepatitis B viral DNA in liver and serum of asymptomatic carriers.

Cloned DNA probes were used to test for hepatitis B virus (HBV) DNA in the liver and serum of 14 asymptomatic hepatitis B surface antigen (HBsAg) carriers and two former carriers. The results were compared with serological markers of HBV infection and liver histopathology. Three groups of carriers were distinguished. In group I, HBV DNA was present in both liver and serum. Hepatitis B e antigen (HBeAg), a marker of viral replication, was uniformly positive in serum. In one individual in this group, viral DNA was also integrated into liver genomic DNA. In group II, lower levels of nonintegrated HBV DNA were detected in the liver, but no HBV DNA was found in the serum. HBeAg was negative and with one exception there were antibodies to HBeAg. Integrated viral DNA was present in each case. In group III, there was no detectable nonintegrated viral DNA in serum or liver, but one individual had integrated sequences. All carriers lacked antibodies to HBsAg and had antibodies to hepatitis B core antigen and demonstrated nonspecific histological abnormalities in the liver. These findings indicate significant quantitative and qualitative differences among asymptomatic HBsAg carriers and suggest that their infectivity may be highly variable.

Adolescent↗
PubMed1982

Properties of a polymorphic DNA segment in the 5' flanking region of the human insulin gene.

The 5' flanking region of the human insulin gene contains a section of variable as to length and sequence. This polymorphic region begins 363 bp from the 5' end of the gene and extends upstream for a variable distance. The restriction fragment length heterogeneity is generated by variation in the redundancy of a family of 14-15 bp GC-rich oligonucleotides. The most frequent, as well as the consensus, sequence for this family is ACAGGGGTGTGGGG. The DNA sequence heterogeneity is produced by differences in the arrangement of members of this oligonucleotide family within the tandemly repeating array. On the basis of differences in restriction fragment length, 40 of 74 (56%) unrelated individuals we have examined have been designated heterozygous at this site. The properties of this region make it a useful molecular marker for this region of chromosome 11 as well as loci within 10-20 million base pairs.

Base Sequence↗
PubMed1981

On the mechanism of variation of pancreatic amylase levels in mouse strains.

The relative levels of pancreatic amylase mRNA closely parallel the 3-fold variation of pancreatic amylase protein levels observed in several mouse strains studied. In contrast pancreatic elastase mRNA levels were similar in these strains. Each of the strains contained the same number of amylase-like genes (about 8). The selective variation in the pancreatic amylase gene expression could be due either to differences in the numbers of active amylase genes or to different rates of synthesis and/or degradation of the amylase mRNA from a constant number of genes.

Amylases↗
PubMed1981

The prolactin gene is located on chromosome 6 in humans.

The gene for prolactin has been located on chromosome 6 in humans. DNA fragments of 4.8 and 4.0 kilobases containing prolactin gene sequences were identified in human genomic DNA, whereas DNA fragments of 7.4, 3.6, and 3.3 kilobases containing prolactin gene sequences were found in mouse cells. In somatic cell hybrids of human and mouse cells the 7.4-, 3.6-, and 3.3-kilobase mouse fragments were always present, whereas the 4.8- and 4.0-kilobase human fragments were only present when human chromosome 6 was also present. We conclude that the prolactin gene resides on chromosome 6, a different location from those of the genes for the related hormones chorionic somatomammotropin and growth hormone.

Animals↗
PubMed1981

Pancreas-specific genes: structure and expression.

Via recombinant DNA technology the mRNA sequence of pancreatic amylase has been cloned and its nucleotide sequence has been determined. The cloned sequence represents 96% of the total length of amylase mRNA; missing are an estimated 75 +/- 30 nucleotides from the 5' end. The amino acid sequence of rat pancreatic amylase was deduced solely from the nucleotide sequence of the mRNA. Unlike other eukaryotic mRNAs, the amylase mRNA has short 5' and 5' untranslated regions, suggesting that long untranslated regions of eukaryotic mRNAs either do not contain extensive functional sequences or that these sequences are incorporated within the amino acid coding region of amylase mRNA. The cloned amylase mRNA sequence was radiolabeled and used as a probe for in situ hybridization. These experiments demonstrate that amylase mRNA is present in all acinar cells but not in other pancreatic cell types. Using the cloned amylase mRNA sequences as a hybridization probe, three nonoverlapping genomic DNA fragments containing amylase gene sequences were isolated. From the similar sequence organization of the three amylase genes visualized by DNA heteroduplex mapping, a consensus structure of a rat amylase gene is proposed. It is an extended gene structure 10 kilobase pairs in length containing the 1547 base pairs of the cloned mRNA coding sequence interrupted by seven intervening sequences ranging from 400-2000 base pairs long. Thus, in nuclear DNA the amylase mRNA coding sequence is disrupted into at least eight segments from 150-300 base pairs long.

Amino Acid Sequence↗