An oligonucleotide hybridization procedure has been developed that eliminates the preferential melting of A X T versus G X C base pairs, allowing the stringency of the hybridization to be controlled as a function of probe length only. This technique, which uses tetramethylammonium chloride, is especially helpful whenever a highly complex library is screened with a pool of oligonucleotide probes, which usually vary widely in base composition. The procedure can also be applied advantageously whenever an exact match to an oligonucleotide probe is desired, such as in screening for clones having as little as a single-base alteration generated by in vitro mutagenesis.

Base Composition↗

PubMed1983

Molecular genetics of human serum albumin: restriction enzyme fragment length polymorphisms and analbuminemia.

By using cDNA probes for the human albumin gene, four restriction enzyme fragment length polymorphisms (RFLPs) were discovered that were transmitted by codominant autosomal inheritance. Among Caucasians, the gene frequencies were 0.04/0.96 for Msp I/5', 0.43/0.57 for Hae III/3', 0.44/0.56 for Hae III/5', and 0.04/0.42/0.54 for Pst I/5'. These common variants provide a marker for chromosome 4 (q11-q13). A calculation of the extent of DNA variation at the albumin locus revealed that 1/95 nucleotide sites was affected by a RFLP, a figure similar to that found in the globin system. Restriction enzyme fragment study of the DNA of a human analbuminemic individual revealed no gross structural rearrangements of the albumin locus. The exact nature of abnormality will require more study.

Alleles↗

PubMed1982

Cloning and expression of the cDNA for human antithrombin III.

A partial cDNA clone for human antithrombin III (ATIII) was obtained by screening a cDNA library prepared from size fractionated liver RNA with a pool of eight 16-base long synthetic DNA fragments whose sequence was determined from protein sequence data. A fragment of the partial cDNA clone was used to enrich RNA for ATIII messages, and cDNA clones encoding the entire ATIII structural gene were identified. The complete nucleotide and predicted amino acid sequences of human ATIII and its 32 residue signal peptide are reported, and provide further opportunity to compare the ATIII primary structure with corresponding regions from homologous proteins, alpha 1-antitrypsin and ovalbumin. Plasmids in which the structural genes for mature and pre-ATIII were linked to the E. coli trp promoter-operator support the synthesis of human antithrombin III and pre-antithrombin III in bacteria.

Amino Acid Sequence↗

PubMed1982

Clustering of leukocyte and fibroblast interferon genes of human chromosome 9.

At least ten leukocyte interferon genes and the single known fibroblast interferon gene have been localized on the pter leads to q12 region of human chromosome 9. Gene mapping was accomplished by blot hybridization of cloned interferon complementary DNA to DNA from human-mouse cell hybrids with a translocation involving human chromosome 9. Supporting evidence suggests these genes are clustered.

Chromosome Mapping↗

PubMed1982

Chromosomal localization of human leukocyte, fibroblast, and immune interferon genes by means of in situ hybridization.

Recombinant plasmids containing cDNA inserts from human leukocyte interferon (IFN-alpha), fibroblast interferon (IFN-beta), or immune interferon (INF-gamma) genes were radiolabeled and hybridized in situ to human metaphase chromosome preparations. The results localized the human IFN-alpha and IFN-beta genes to the short arm of chromosome 9(p21-->pter) and localized the IFN-gamma gene to the long arm of chromosome 12(q24.1).

Chromosome Banding↗

PubMed1982

Carboxyterminal region of hybrid leukocyte interferons affects antiviral specificity.

Four hybrid human leukocyte interferon (IFN-alpha) genes have been constructed and expressed in Escherichia coli using molecular cloning methods. Plasmids containing genes encoding human interferons, IFN-alpha A, IFN-alpha D, IFN-alpha I and several hybrids of the different IFN-alpha genes (formed by in vitro recombination at common restriction endonuclease sites located within the DNA sequence encoding mature polypeptides) joined identically to an E. coli trp promoter gave rise to bacterial-produced interferons with distinctly different antiviral activities. The expression plasmid which directs the synthesis of IFN-alpha I was constructed using a gene isolated from a human genomic library in a manner similar to the previous expression of IFN-alpha A and IFN-alpha D cDNA clones. The use of a cell-free transcription-translation system has allowed the calculation of the specific activities of IFN-alpha made from isolated DNA fragments containing these hybrid IFN-alpha genes. These bacterially-derived interferons vary considerably in their ability to inhibit vesicular stomatitis virus (VSV) in different mammalian cells. The results show that the cloned hybrid interferons have unique antiviral activities when compared with the parent interferons, and they demonstrate that more active IFN-alpha s can be made using recombinant DNA techniques.

Amino Acid Sequence↗

PubMed1982

Greek (A gamma) variant of hereditary persistence of fetal haemoglobin: globin gene organization and studies of expression of fetal haemoglobins in clonal erythroid cultures.

Individuals heterozygous for the Greek (A gamma) variant of hereditary persistence of fetal haemoglobin (HPFH) synthesize Hb F whose gamma-globin chains are predominantly of the A gamma type. DNA obtained from Greek HPFH heterozygotes was used to test for abnormalities in the organization of non alpha-globin genes. In addition, gamma- and beta-globin expression was studied in BFUe cultures. Restriction endonuclease mapping showed that the G gamma, delta and beta genes in cis to the Greek HPFH determinant are intact. Overproduction of gamma-globin chains synthesis was observed in the BFUe cultures. A significant portion of the gamma chain synthesis was of the G gamma type, suggesting that the G gamma genes cis and trans to the HPFH chromosome are active in culture. DNA mapping data indicate that in contrast to G gamma A gamma HPFH and the G gamma (delta beta) thalassaemia, the Greek (A gamma) HPFH is not due to a large deletion in the non-alpha globin gene region. It is possible that the anomaly may result either from a small deletion or point mutation which influences non alpha-globin transcription. The in vitro synthesis data suggest that the low level of G gamma-globin chain synthesis in vivo is not the result of transcriptional inactivation of the G gamma gene, since this gene appears to be expressed in erythroid cell cultures. We speculate that the genetic lesion in Greek (A gamma) HPFH is in regulatory sequences which control the level of G gamma and A gamma expression during development.

Adult↗

PubMed1981

The sequence of human serum albumin cDNA and its expression in E. coli.

A recombinant plasmid has been constructed which contains the mature protein coding region of the human serum albumin (HSA) gene. Bacteria containing this plasmid synthesize HSA protein under control of the E. coli trp promoter-operator. The DNA sequence and predicted protein sequence of HSA were determined from the cDNA plasmid and are compared to existing data obtained from direct protein sequencing. The DNA sequence predicts a mature protein of 585 amino acids preceded by a 24 amino acid "prepro" peptide.

Amino Acid Sequence↗

PubMed1981

DNA sequence of two closely linked human leukocyte interferon genes.

A single recombinant lambda bacteriophage isolated from a human genome library contains two closely related human interferon genes of the leukocyte or alpha type. The two genes are separated by 12 kilobase pairs and are oriented in the same direction with respect to transcription. Comparisons of the DNA sequences of these two genes and interferon complementary DNA clones indicate that the two interferon genes lack intervening sequences.

Bacteriophage lambda↗

PubMed1981

Human fibroblast interferon gene lacks introns.

A recombinant lambda bacteriophage isolated from a human genome library contains the gene for fibroblast interferon (IFN-beta1). The DNA sequence of this gene is identical to the sequence of its mRNA and is devoid of introns.

Bacteriophage lambda↗

PubMed1981

The structure of eight distinct cloned human leukocyte interferon cDNAs.

Eight classes of human leukocyte interferon (LeIFN) cDNA clones have been identified in a cDNA library prepared from a myeloblastoid cell line. The nucleotide sequences demonstrate that the multiple human LeIFN genes code for a family of homologous, yet distinct proteins. One of the cDNA clones may have been derived from the transcription of a LeIFN pseudogene.

Amino Acid Sequence↗

PubMed1981

Leukocyte and fibroblast interferon genes are located on human chromosome 9.

At least eight leukocyte interferon genes (IFL) and the single fibroblast interferon gene (IFF) have been located on chromosome 9 in humans. In somatic cell hybrids of human and mouse cells containing a normal complement of mouse parental cell chromosomes but reduced numbers of human chromosomes, the human leukocyte and fibroblast interferon DNA sequences were present only when human chromosome 9 was also present.

Animals↗

PubMed1981

DNA sequence of a major human leukocyte interferon gene.

The gene for human leukocyte interferon alpha 2 (designated either LeIF A or HuIFN-alpha 2) has been isolated from a human genome library. The DNA sequence of this gene demonstrates that it lacks introns. The 3' noncoding sequences of the IFN-alpha 2 gene correspond to two types of IFN-alpha 2 cDNA clones we have isolated that have alternate sites of polyadenylylation. A comparison of seven human IFN-alpha sequences shows that they are homologous in the 5' flanking region and contain identical "TATA box" sequences. The recombinant lambda clone containing the IFN-alpha 2 gene also contains two copies of the "Alu family" repeat sequence.

Amino Acid Sequence↗