Luc d'Auriol

Complete amino acid sequence of the human progesterone receptor deduced from cloned cDNA

A lambda gt10 library containing DNAs complementary to messenger RNAs from human breast cancer T47-D cells was constructed and screened with a cDNA probe encoding the rabbit progesterone receptor. Four overlapping clones have been sequenced. The open reading frame corresponds to a protein of 933 amino acids with a molecular weight of 98,868 Da. The cysteine rich basic region supposed to be involved in DNA binding is completely homologous in the human and rabbit receptors, whereas the C-terminal end, where hormone binding is thought to take place, differs by a single amino acid change. The human progesterone receptor is characterized, as is the rabbit receptor, by the very high proline content of its N-terminal region. When mRNAs from either human breast cancer cell lines T47-D and MCF-7 or from normal human uterus tissue were blotted and probed with the cloned cDNA, four main bands were observed (5100, 4300, 3700, and 2900 nucleotides).

A natural antisense RNA derived from the HIV-1 env gene encodes a protein which is recognized by circulating antibodies of HIV+ individuals

A naturally occurring antisense RNA, transcribed in the opposite direction and complementary to the envelope transcript, was identified in various cell lines chronically infected with HIV-1. In T cells, the antisense transcript is constitutively expressed and enhanced by activation with phorbol myristate acetate. The open reading frame corresponding to the antisense transcript, when expressed in vitro, encodes a protein with an apparent molecular mass of 19 kDa. Antibodies against this protein have been detected in several sera of HIV+ individuals and not in any of the noninfected control sera. These results indicate, for the first time, that expression of an antisense open reading frame most likely accompanies the HIV infection cycle in humans.

Molecular cloning and nucleotide sequence of a cDNA clone coding for rat brain myelin proteolipid

A cDNA library from rat brain was constructed in pBR322 and screened with a 14‐mer mixed oligonucleotide probe based on residues 231–235 of bovine proteolipid (PLP). A positive clone was isolated: it contained a 1334‐base‐pair cDNA insert and was subjected to DNA sequence analysis. The cDNA encoded information for the 276 amino acids of rat PLP. Comparison with bovine PLP sequence showed a complete amino acid sequence homology except for 4 amino acid residues.

Cloning and sequencing of Plasmodiumfalciparum DNA fragments containing repetitive regions potentially coding for histidine-rich proteins: identification of two overlapping reading frames

DNA sequences, potentially coding for histidine-rich proteins, were isolated from a P. falciparum genomic library using an oligonucleotide probe consisting of histidine codon repeats. Sequencing revealed that the different DNA fragments contain long repetitive regions very homologous to the probe. One clone was fully sequenced and contains two open reading frames that overlap in the repetitive region but are located on opposite strands. Analysis suggests that both are coding. One frame could code for a small histidine-rich protein, the other for a protein containing many aspartic acid residues. Southern blotting revealed that these sequences are conserved in all three P. falciparum strains studied.

Acute T‐cell leukemia/lymphoma mimicking Hodgkin's disease with secondary HTLV I seroconversion

The authors observed a pleiomorphic lymphoma mimicking Hodgkins lymphoma in a French Guyana black woman lacking antibodies for human T‐cell lymphoma/leukemia virus type I (HTLV I). After two courses of chemotherapy with either mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) or doxorubicin, bleomycin, vincaleukoblastine, and dacarbazine (ABVD), a typical acute T‐cell leukemia/lymphoma developed with HTLV I seroconversion. Specific HTLV I DNA sequences were detected using the polymerase chain reaction (PCR) on a lymph node biopsy obtained before chemotherapy. The mechanisms of the seroconversion are discussed.

On the high conservation of the human c-myc first exon

Several hypotheses have been proposed to explain the role that the human c-myc 1st exon is thought to play in the regulation of the expression of the c-myc protein. One of these hypotheses, based on sequencing data showing an open reading frame overlapping that exon, predicts the existence of a protein most probably involved in the regulation of the expression of the c-myc protein. However, mainly because several other published sequences are devoided of such an ORF, this hypothesis did not retain much attention. In this paper, we present two additional sequences fully identical to the 1st exon region sequence we previously published, and discuss the implication of such a high degree of conservation for the human c-myc 1st exon.

Nucleotide sequence analysis of the LTRs and env genes of SM-FeSV and GA-FeSV

The nucleotide sequences of the env genes and the LTRs of SM- and GA-FeSV lambda recombinants have been determined by the Maxam and Gilbert method and/or the dideoxy method with specific sequencing primers. Comparison of the two sequences reveals a homology of 93%, the differences being randomly distributed. Two frameshift mutations are observed in the GA-FeSV isolate which close the reading frame and would prevent the synthesis of the env protein. Comparison of these two FeSV sequences with the env sequences of each antigenic subgroup of FeLV (A, B, C) reveals that these two viruses can be assigned to the A/C subgroups.

In vitro growth properties and PCR ras gene analysis of a murine embryonal carcinoma cell line harboring an amplified C-Ki-ras gene

Ras proto‐oncogenes are thought to be involved in both proliferation and malignant processes. We examined some growth properties of a murine embryonal carcinoma cell line (ECC), PCC4, that have been shown previously to be amplified for the c‐KI‐ras gene. Our results show that doubling time and plating efficiency are not significantly affected by such amplification. To examine the possible link between malignant behavior and c‐Ki‐ras alteration, we investigated activating mutations in this PCC4 cell line as well as in other ECC. Analysis of the in vitro amplified Ki‐ras gene by PCR technology has not revealed point mutations in any of the ECC examined.