PubMed Health⌕ Search

Biomedical subjects

J M Garnier

Publications and source records attributed to J M Garnier.

At least 73 records · Page 4Linked to original sources
PubMed1995

Efficient cloning of cDNAs of retinoic acid-responsive genes in P19 embryonal carcinoma cells and characterization of a novel mouse gene, Stra1 (mouse LERK-2/Eplg2).

Pluripotent mouse P19 embryonal carcinoma (EC) cells have been extensively used as a developmental model system because they can differentiate in the presence of retinoic acid (RA) into derivatives of all three germ layers depending on RA dosage and culture conditions. The expression of several genes has been shown to be induced in RA-treated P19 EC cells and, interestingly, some of these genes may play important roles during mouse embryogenesis. In view of the increasing evidence that RA is a crucial signaling molecule during vertebrate development, we have initiated a study aimed at the systematic isolation of genes whose expression is induced in P19 cells at various times after exposure to RA. We describe here an efficient differential subtractive hybridization cloning strategy which was used to identify additional RA-responsive genes in P19 cells. Fifty different cDNA fragments corresponding to RA-induced genes were isolated. Ten cDNAs represent known genes, 4 of which have already been described as RA-inducible, while the remaining 40 correspond to novel genes. Many of these cDNA sequences represent low-abundance mRNAs. Kinetic analysis of mRNA accumulation following RA treatment allowed us to characterize four classes of RA-responsive genes. We also report the sequence and expression pattern in mouse embryos and adult tissues of one of these novel RA-inducible genes, Stra1, and show that it corresponds to the mouse ligand for the Cek5 receptor protein-tyrosine kinase.

Animals↗
PubMed1995

Transcripts from opposite strands of gamma satellite DNA are differentially expressed during mouse development.

Using in vitro immuno-selected retinoic acid response elements, we have isolated mouse genomic clones containing major (gamma) satellite DNA repeats that are considered as typical of chromosome centromeres. Several cDNA clones were then isolated from a F9 cell cDNA library and were found to harbor variants of the 234-base pair consensus gamma satellite monomer. In Northern analysis, these satellite DNA sequences hybridized predominantly to an approximately 1.8-kb RNA species in polyadenylated RNA from P19 cells. These transcripts were strongly repressed by retinoic acid, and nuclear run-on assays revealed that this repression was, at least in part, mediated at the transcriptional level. Satellite transcripts were also detected in HeLa cells, where they were similarly down-regulated by retinoids. Heterogeneously sized satellite transcripts were detected in RNA from specific mouse tissues, such as fetuses (but not placenta), adult liver, and testis. In situ hybridization analysis revealed that satellite transcripts are generated from opposite DNA strands and are differentially expressed in cells of the developing central nervous system as well as in adult liver and testis. These data may have implications on retinoic acid-mediated transcriptional regulation and centromere function.

Age Factors↗
PubMed1995

Characterization of cDNAs encoding two chick retinoic acid receptor alpha isoforms and distribution of retinoic acid receptor alpha, beta and gamma transcripts during chick skin development.

The amino acid sequence of the retinoic acid receptors alpha, beta and gamma (RAR alpha, beta and gamma) can be divided into six functional domains (A-F), different isoforms arising from the presence of different A domains by differential splicing. In order to address the respective roles of the different RARs during skin morphogenesis in birds, cDNAs encoding two chick RAR alpha isoforms (alpha1 and alpha2) have been isolated. While the A1 and B-F domains of the RAR alpha are highly conserved across species, the chick A2 domain contains 50% specific amino acids. The three RAR alpha, beta and gamma genes display specific patterns of expression during chick skin morphogenesis. As in mouse, RAR alpha and gamma transcripts are present in both the dermis and epidermis during the first stages of skin appendage formation. Furthermore, Northern blot analysis suggests that different RAR alpha and gamma isoforms could be successively required during feather formation. The RAR gamma gene, continuously expressed in the epidermal cells in both chick and mouse, is thus likely to play a similar role in skin development in these two species. However, RAR alpha transcripts, only transiently detected during mouse skin development, still accumulate in epidermis during the later stages of chick skin differentiation. Furthermore, RAR beta transcripts, never detected during normal development in mouse skin, are actually present at the early stages of chick skin morphogenesis. Thus, our results suggest that the role of the three RAR in skin development has not been strictly conserved in the different classes of vertebrates.

Amino Acid Sequence↗
PubMed1994

Cloning of the cDNA encoding rat tissue inhibitor of metalloproteinase 1 (TIMP-1), amino acid comparison with other TIMPs, and gene expression in rat tissues.

We have cloned the cDNA encoding the rat tissue inhibitor of metalloproteinase 1 (TIMP-1) from a cDNA library derived from healing skin wounds. The deduced amino acid (aa) sequence shows 66, 35 and 34% identity with human TIMP-1 and TIMP-2, and chicken TIMP-3 aa sequences, respectively. High-level expression of rat TIMP-1 RNA was detected in the skin wounds and in normal ovary.

Amino Acid Sequence↗
PubMed1994

A previously unidentified choline acetyltransferase transcript in the human foetal brain.

To identify choline acetyltransferase (ChAT) transcript(s) in human foetal brain we used the reverse polymerase chain reaction including different couples of oligonucleotide primers. The analysis indicated the presence of a new choline acetyltransferase transcript containing at its 5' end an untranslated exon (E1A) of 57 nucleotides in length extending from Nt 3771 to Nt 3828. It differs in the 5'-non coding region from the M-N-R type mRNA previously described in mouse and rat.

Brain↗
PubMed1994

Lysyl oxidase cDNA of myofibroblast from mouse fibrotic liver.

In order to study the regulation of lysyl oxydase (LO) in fibrosis, mRNAs were extracted from an enriched population of myofibroblasts (MF) isolated from liver of schistosomiasis infected mouse. Four mRNAs (5.5kb, 4.5kb, 2.4kb and 2.0kb) hybridizing with a LO cDNA probe were transcribed in fibrotic liver, but only the two largest mRNAs were found in MF. A cDNA library was constructed, allowing the cloning of twenty four cDNAs. The largest clone of 4689bp should correspond to the 5.5kb mRNA. Its sequence was essentially similar to the NIH-3T3 fibroblasts LO-ras recision gene (rrg4) cDNA, with the same exon/intron structure, but with some differences at the sites of initiation of transcription which were shown to occur mainly at -392 and -358 nucleotides before the putative start of translation. These two main sites of initiation did not explain the origin of the 4.5kb and 5.5kb mRNAs, and as no spliced variants were found among the 24 clones, some regulation should also involve the 3'end region.

Animals↗
PubMed1994

Characterization of cDNAs encoding the chick retinoic acid receptor gamma 2 and preferential distribution of retinoic acid receptor gamma transcripts during chick skin development.

Retinoic acid receptors alpha, beta and gamma (RAR alpha, beta and gamma) are ligand-inductible transcriptional activators which belong to the steroid/thyroid hormone receptor superfamily. At least two major isoforms (1 and 2) of each RAR arise by differential use of two promoters and alternative splicing. In mouse, the three RAR genes are expressed in stage- and tissue-specific patterns during embryonic development. In order to understand the role of the different RARs in chick, RAR gamma 2 cDNAs were isolated from an 8.5-day (stage 35 of Hamburger and Hamilton) chick embryo skin library. The deduced chick RAR gamma 2 amino acid sequence displays uncommon features such as 21 specific amino acid replacements, 12 of them being clustered in the amino-terminal region (domains A2 and B), and a truncated acidic carboxy-terminal region (F domain). However, the pattern of RAR gamma expression in chick embryo resembles that reported in mouse, particularly in skin where RAR gamma expression occurs in both the dermal and epidermal layers at the beginning of feather formation, and is subsequently restricted to the differentiating epidermal cells. Northern blot analysis suggests that different RAR gamma isoforms could be successively required during chick development.

Amino Acid Sequence↗
PubMed1994

[Pulmonary tuberculosis in infants. Apropos of 6 cases].

BACKGROUND: The present increased incidence of tuberculosis in children can be explained by contacts with infected adults and/or late BCG vaccination. PATIENTS: Six infants, 3 to 18 months-old (mean: 8 months), were admitted from November 1990 to May 1992 for various reasons; only two were admitted with a diagnosis of tuberculosis based on tuberculin test and only one was given a BCG vaccine. The disease produced a broad range of symptoms. Diagnosis was based on tuberculin test and radiographic examination showing lymph node enlargement of mediastinum and segmental consolidation lesions. Mycobacterium tuberculosis was found in two cases. The patients were given isoniazid, rifampin, ethambutol and/or pyrazinamide; corticosteroids were added in five patients. Each patient received four or three drugs for 2-4 months and two drugs (isoniazid plus rifampin) beyond, for a mean total duration of 13 months (range: 9-17 months). Repeated CT scan of thorax was performed to evaluate the efficacy of treatment. Tuberculosis was diagnosed in 11 subjects in contact with these children. CONCLUSION: Tuberculosis in children is not rare, and BCG vaccination of neonates should be seriously considered.

BCG Vaccine↗
PubMed1994

[Subcapsular liver hematoma, a HELLP syndrome complication].

The authors report a case of unruptured subcapsular haematoma of the liver in a 31-year-old woman, para 2, in the 34th week of pregnancy, complicated by preeclampsia. Clinical signs of preeclampsia were associated with pain in the right hypocondrium and laboratory findings consistent with a true HELLP syndrome. The diagnosis of subcapsular haematoma was confirmed by tomodensimetry. A cesarean section was carried out but a conservative treatment of the hepatic haematoma was decided. Regular X-ray follow-ups showed the regression of the hepatic lesion. This case confirms recent reports that patients with unruptured capsular haematoma should be treated conservatively but should receive careful monitoring.

Adult↗
PubMed1993

Cloning a pseudogene and cDNA encoding a 17-kDa ribosomal protein from mouse: structure and regulation of expression.

An rp lambda 5 cDNA encoding a ribosomal protein (r-protein) and a pseudogenic form of the corresponding gene (rp lambda 7) have been cloned from mouse. This cDNA codes for a highly basic protein of 160 amino acids (aa) with a deduced M(r) of 17,601, and most likely represents the species homolog of a recently cloned rat cDNA, which has been proposed to encode a homolog of the yeast r-protein, YL43. The entire rp lambda 5 gene encompasses less than 1.5 kb of genomic DNA and apparently is composed of only two exons, as deduced from sequence comparison with its very similar pseudogenic variant, rp lambda 7. Southern analysis, using the rp lambda 5 cDNA as a probe, indicates the existence of a great number of highly related sequences in the mouse genome. The mRNA for rp lambda 5 is approximately 800 nucleotides (nt) long and is found to be ubiquitously expressed at high levels in embryonic and adult mouse tissues, as shown by Northern and in situ analyses. Retinoic acid (RA) seems to have a moderate down-regulatory effect on this mRNA in differentiating P19 embryonal carcinoma cells. Several degenerate/nondegenerate RA-response element (RARE) motifs are found within 560 bp upstream from the degenerate start codon in rp lambda 7. However, it is unknown whether this RA effect is exerted at the transcriptional and/or posttranscriptional levels.

Amino Acid Sequence↗
PubMed1993

Isolation and sequence of a cDNA encoding the Jerusalem artichoke cinnamate 4-hydroxylase, a major plant cytochrome P450 involved in the general phenylpropanoid pathway.

Cinnamate 4-hydroxylase [CA4H; trans-cinnamate,NADPH:oxygen oxidoreductase (4-hydroxylating), EC 1.14.13.11] is a cytochrome P450 that catalyzes the first oxygenation step of the general phenylpropanoid metabolism in higher plants. The compounds formed are essential for lignification and defense against predators and pathogens. We recently reported the purification of this enzyme from Mn(2+)-induced Jerusalem artichoke (Helianthus tuberosus L.) tuber tissues. Highly selective polyclonal antibodies raised against the purified protein were used to screen a lambda gt11 cDNA expression library from wound-induced Jerusalem artichoke, allowing isolation of a 1130-base-pair insert. Typical P450 domains were identified in this incomplete sequence, which was used as a probe for the isolation of a 1.7-kilobase clone in a lambda gt10 library. A full-length open reading frame of 1515 base pairs, encoding a P450 protein of 505 residues (M(r) = 57,927), was sequenced. The N terminus, essentially composed of hydrophobic residues, matches perfectly the microsequenced N terminus of the purified protein. The calculated pI is 9.78, in agreement with the chromatographic behavior and two-dimensional electrophoretic analysis of CA4H. Synthesis of the corresponding mRNA is induced in wounded plant tissues, in correlation with CA4H enzymatic activity. This P450 protein exhibits the most similarity (28% amino acid identity) with avocado CYP71, but also good similarity with CYP17 and CYP21, or with CYP1 and CYP2 families. According to current criteria, it qualifies as a member of a new P450 family.

Amino Acid Sequence↗
PubMed1993

Molecular cloning of a cDNA encoding a nerve growth factor precursor from the krait, Bungarus multicinctus.

NGFs have been isolated from the venom of many snakes. Here we report the isolation and the sequencing of a nearly full-length NGF cDNA from the Bungarus multicinctus venom gland cDNA library. The structure of the predicted krait precursor resembles that of cobra and of other animals, with a highly conserved mature NGF protein at the carboxy-terminus. Prepro part of the precursors are less conserved. The krait one possesses the presumptive 18 amino residues terminal signal sequence and the two long stretches corresponding to functional domains which are highly conserved alternating with large poorly conserved regions. We discuss particularities in the sequence of the precursor in the krait which may in part explain some earlier results obtained concerning this factor in the krait venom.

Amino Acid Sequence↗
PubMed1993

[Breast reconstruction with inferior transverse abdominal flap after mastectomy for cancer].

Breast reconstruction with an inferior transversal abdominal flap provides good quality cosmetic results. Indications for this flap technique are presently limited because of the frequency of complications in early series. The aim of this study was to evaluate the different parameters which could reduce the number of complications. From January 1989 to July 1991, 25 patients were treated with this method at the René-Gauducheau Centre. All patients were treated with the same surgical technique. Based on the complications observed in this series and a review of the literature, we were able to determine those factors which could limit the number of complications. Preoperative patient selection defined a population at risk of vascular complications. This population corresponded to a good indication for double pediculated flaps. Global flap removal, the muscle and the anterior sheath of the aponevrose together, and maintaining the patient in a sitting position for five days after the operation helped reduce the frequency of complications. Folding the abdominal wall with a nonabsorbable sheath appeared to be a simple and reliable method of reducing the number of abdominal complications. The double pediculated flap was indicated in all cases at risk of partial necrosis or when a large volume was necessary to avoid asymmetry. Using this type of management, breast reconstruction with inferior transversal abdominal flap is the first intention technique used at the René-Gauducheau Centre in Nantes.

Abdominal Muscles↗
PubMed1993

[Unusual intrathoracic tumor in children: lipoma].

BACKGROUND: Intrathoracic lipomas are rare, often asymptomatic and, in this case, discovered by chance on X-ray. CASE REPORT: A 3 year-old girl was admitted because chest X-rays prescribed for a persistent cough showed a mass in the right axillary area. The CT scan showed a mass with density of -80 Hounsfield units, characteristic of adipose tissue. There was a slight rib change in contact with the mass, but radionuclide bone scan showed no area of increased uptake. A chest X-ray performed 3 years earlier had shown such a mass, but it was not recognized at that time. Surgery demonstrated that the mass was extrapleural in location and adhering to the rib which was partly excised. Histologic examination showed the presence of mature adipocytes, but no malignant cells. CONCLUSION: The fatty component of an intrathoracic tumor is easily recognized with CT scan. Erosion of bone in contact with it has been reported.

Age Factors↗
PubMed1993

[A new approach to the axilla: functional axillary lymphadenectomy and padding].

Axillary lymph node dissection, which is now mandatory in the conservative breast cancer surgery and classically involves Berg's two lower levels, is burdened with numerous complications. In 1988 and 1989, two technical modifications were introduced and are described here: padding of the axilla as preventive treatment of postoperative lymphocele and, more recently, functional axillary lymphadenectomy (FAL) in which the medial cutaneous nerve of the arm, the two perforating intercostal nerves and above all the lateral thoracic pedicle (external mammary artery and vein) are spared. These two technical innovations, more respectful of anatomy, are aimed at reducing the morbidity of conservative breast cancer at a time when detection enables breast cancers to be treated at an increasingly early stage, which results in a increase of negative axillary dissections. The postoperative period is simplified (no drainage, immediate mobilization), and the hospital stay is reduced to 2 days. Complementary treatments can thus be started early on, without any functional or cosmetic damage while the number of lymph nodes removes remains the same as in the conventional axillary dissection technique. The authors describe the operative procedures and analyse the 100 cases of conservative breast cancer they have treated with padding and FAL. These two technical modifications are now systematically used by them in the management of breast cancers.

Axilla↗
PubMed1992

Purification, cloning, and RXR identity of the HeLa cell factor with which RAR or TR heterodimerizes to bind target sequences efficiently.

We have purified and cloned a HeLa cell nuclear protein that strongly stimulates binding of retinoic acid and thyroid hormone receptors (RARs and TRs) to response elements. The purified protein is a human retinoid X receptor beta (hRXR beta). Three murine members of the RXR family (mRXR alpha, beta, and gamma) have also been cloned, and their interactions with RARs and TRs have been investigated. Under conditions where RAR, RXR, and TR bound poorly as homodimers to various response elements, strongly cooperative RAR-RXR and TR-RXR binding was observed. The binding efficiency was dependent on the sequence, relative orientation, and spacing of the repeated motifs of response elements. We show also that unstable RAR-RXR heterodimers were formed in solution, and that C-terminal sequences and the DNA-binding domains of both receptors were required for efficient formation of stable heterodimers on response elements. These findings suggest a convergence of the signaling pathways of some members of the nuclear receptor superfamily.

Amino Acid Sequence↗