Biomedical subjects

B Haendler

Publications and source records attributed to B Haendler.

43 records · Page 3Linked to original sources

PubMed1989

Yeast cyclophilin: isolation and characterization of the protein, cDNA and gene.

Cyclophilin (CPH) has been isolated from the yeast Saccharomyces cerevisiae, purified to homogeneity and partially sequenced. Oligodeoxyribonucleotides deduced from this sequence were used to isolate the corresponding cDNA and gene. An open reading frame coding for a 162-amino acid (aa) protein with a calculated Mr of 17,392, was deduced from the nucleotide sequence. Comparison between yeast and human CPH shows a very high overall sequence conservation (65% aa homology). The binding of yeast CPH to cyclosporin A is identical to that of human and bovine CPH. Unlike in Neurospora crassa, a mitochondrial form of CPH could not be detected in yeast. Southern-blot analysis of yeast DNA shows that only one CPH-related sequence is present per haploid genome, whereas at least 20 genes or pseudogenes were detected in the human and rat genome. Purified yeast CPH exhibits peptidyl-prolyl cis-trans isomerase activity, albeit to a far lesser extent than the mammalian protein.

Amino Acid Sequence↗

PubMed1987

Complementary DNA for human glioblastoma-derived T cell suppressor factor, a novel member of the transforming growth factor-beta gene family.

Human glioblastoma cells secrete a peptide, termed glioblastoma-derived T cell suppressor factor (G-TsF), which has suppressive effects on interleukin-2-dependent T cell growth. As shown here, complementary DNA for G-TsF reveals that G-TsF shares 71% amino acid homology with transforming growth factor-beta (TGF-beta). In analogy to TGF-beta it is apparently synthesized as the carboxy-terminal end of a precursor polypeptide which undergoes proteolytic cleavage to yield the 112 amino-acid-long mature form of G-TsF. Comparison of the amino-terminal sequence of G-TsF with that of porcine TGF-beta 2 and bovine cartilage-inducing factor B shows complete homology, which indicates that we have cloned the human analogue of these factors. It is tempting to consider a role for G-TsF in tumor growth where it may enhance tumor cell proliferation in an autocrine way and/or reduce immunosurveillance of tumor development.

Amino Acid Sequence↗

PubMed1987

Complementary DNA for human T-cell cyclophilin.

Complementary DNA encoding human cyclophilin, a specific cyclosporin A-binding protein, has been isolated from the leukemic T-cell line Jurkat and sequenced. Comparison of the deduced amino acid sequence with the previously determined sequence of bovine thymus cyclophilin reveals only three differences: an additional amino acid at the carboxy terminus end and two internal changes. RNA transfer blot analysis indicates an mRNA size of approximately 1 kb for human T-cell cyclophilin. Phytohaemagglutinin and phorbol myristate acetate induction of T cells treated or not with cyclosporin A affects only marginally the level of cyclophilin mRNA. Southern blot analysis of human genomic DNA digested with different restriction enzymes strongly suggests the existence of a multigene family for cyclophilin.

Amino Acid Sequence↗

PubMed1984

A family of small nucleoplasmic RNAs with common structural features.

The four small nucleoplasmic RNAs designated as U1, U2, U4 and U5 RNA have a common structural domain or domain A. It is characterized by the presence of consensus sequence Pu-A-(U)5-G-Pup in a free single-stranded region and of the sequence Py-N-Py-Gp in the top loop of a hairpin located at the 3' end of the free region. Domain A is likely to be involved in a function common to the four small RNAs. Other domains possibly involved in the specific function of U1 and U5 RNAs are also presented. Several molecular forms of a same U RNA may be found in a same cellular type. These variant U RNAs are particularly numerous for U5 RNA. The possible origin of such new molecular forms is discussed in relation to multigene families for U RNAs. U1, U2, U4 and U5 RNAs are capped (with trimethylguanosine) and the consensus sequence for their 6 first nucleotides is A-(Py)5p. Thus, their 5' end resembles that of premessenger RNA, also capped (with monomethylguanosine) and bearing A-(Py)5p. Both classes of RNA are synthesized by RNA polymerase B, but the presence of a "TATA box" upstream of the capsite has not yet been demonstrated for U RNA genes. U1, U2, U4 and U5 RNAs bear a sequence C-Py-Pu at their 3' end or very close to it. This trinucleotide might be part of a site of post-transcriptional cleavage of U RNA precursors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1983

High evolutionary conservation of the secondary structure and of certain nucleotide sequences of U5 RNA.

The nucleotide sequence of chicken, pheasant, duck and Tetrahymena pyriformis U5 RNAs as well as that of new mammalian variant U5 RNAs was determined and compared to that of rat and HeLa cells U5 RNAs. Primary structure conservation is about 95% between rat and human cells, 82% between mammals and birds and 57% between the Protozoan and mammals. The same model of secondary structure, a free single-stranded region flanked by two hairpins can be constructed from all RNAs and is identical to the model previously proposed for mammalian U5 RNA on an experimental basis (1). Thus, this model is confirmed and is likely to be that of an ancestor U5 RNA. The 3' region of the U5 RNA molecule constitutes domain A, and is common to U1, U2, U4 and U5 RNAs (2). The characteristic nucleotide sequences of domain A are highly conserved throughout the phylogenetic evolution of U5 RNA suggesting that they are important elements in the function of the four small RNAs. Another region of high evolutionary conservation is the top part of the 5' side hairpin whose conserved sequence is specific to U5 RNA. It might participate in the particular function of U5 RNA.

Animals↗

PubMed1983

Two 5S genes are expressed in chicken somatic cells.

Two 5S RNA species were detected in chicken cells. 5S I RNA has the nucleotide sequence of chicken 5S RNA previously published by Brownlee et al. (1) and 5S II RNA differs from it by 10 mutations. The secondary structure of both species is compatible with that proposed for other eukaryotic 5S RNAs. 5S II RNA represents 50-60% of 5S I RNA. Both species were found in total chicken liver and brain and were present in polysomes in the same relative proportions. Only one 5S RNA species could be detected in rat liver and HeLa cells. Chicken is the first vertebrate described so far in which two 5S RNA genes are expressed in somatic cells.

Animals↗

PubMed1982

U2 RNA shares a structural domain with U1, U4, and U5 RNAs.

We previously reported common structural features within the 3'-terminal regions of U1, U4, and U5 RNAs. To check whether these features also exist in U2 RNA, the primary and secondary structures of the 3'-terminal regions of chicken, pheasant, and rat U2 RNAs were examined. Whereas no difference was observed between pheasant and chicken, the chicken and rat sequences were only 82.5% homologous. Such divergence allowed us to propose a unique model of secondary structure based on maximum base-pairing and secondary structure conservation. The same model was obtained from the results of limited digestion of U2 RNA with various nucleases. Comparison of this structure with those of U1, U4, and U5 RNAs shows that the four RNAs share a common structure designated as domain A, and consisting of a free single-stranded region with the sequence Pu-A-(U)n-G-Pup flanked by two hairpins. The hairpin on the 3' side is very stable and has the sequence Py-N-Py-Gp in the loop. The presence of this common domain is discussed in connection with relationships among U RNAs and common protein binding sites.

Animals↗