Genomic DNA PCR analysis to assess xenograft development in mouse mammary gland

The mouse transplantation model remains the most relevant methodology to assess the functional capacities of mammary cells and is particularly appropriate for investigations regarding mammary stem cells, whatever the species studied. Following xenotransplantation in mice mammary fat pad, the development of the xenograft is commonly evaluated by immunohistology. Here, we present a simple and rapid method to control the species specificity of a xenograft based on genomic DNA PCR amplification. DNA is extracted from the fixed samples intended for histology, thus allowing the reuse of precious samples. Standard and digital droplet PCR (requiring low DNA quantities) methods have been used to make the present method suitable for the analysis of xenotransplanted samples

Identification and characterization of new miRNAs cloned from normal mouse mammary gland

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) are small non-coding RNAs that have been found to play important roles in silencing target genes and that are involved in the regulation of various normal cellular processes. Until now their implication in the mammary gland biology was suggested by few studies mainly focusing on pathological situations allowing the characterization of miRNAs as markers of breast cancer tumour classes. If in the normal mammary gland, the expression of known miRNAs has been studied in human and mice but the full repertoire of miRNAs expressed in this tissue is not yet available.</p> <p>Results</p> <p>To extend the repertoire of mouse mammary gland expressed miRNAs, we have constructed several libraries of small miRNAs allowing the cloning of 455 sequences. After bioinformatics' analysis, 3 known miRNA (present in miRbase) and 33 new miRNAs were identified. Expression of 24 out of the 33 has been confirmed by RT-PCR. Expression of none of them was found to be mammary specific, despite a tissue-restricted distribution of some of them. No correlation could be established between their expression pattern and evolutionary conservation. Six of them appear to be mouse specific. In several cases, multiple potential precursors of miRNA were present in the genome and we have developed a strategy to determine which of them was able to mature the miRNA.</p> <p>Conclusion</p> <p>The cloning approach has allowed improving the repertoire of miRNAs in the mammary gland, an evolutionary recent organ. This tissue is a good candidate to find tissue-specific miRNAs and to detect miRNA specific to mammals. We provide evidence for 24 new miRNA. If none of them is mammary gland specific, a few of them are not ubiquitously expressed. For the first time 6 mouse specific miRNA have been identified.</p

Cytogenetic mapping of 25 goat mammary gland Expressed Sequence Tags (ESTs)

Today, there is a shift towards a positional candidate approach in the molecular identification of genes. This study reports on an Expressed Sequence Tags (ESTs) mapping initiative in goats, based on sequence information gathered from a previous mammary gland cDNA systematic sequencing project. A total of 25 novel genes was localised cytogenetically on 16 goat chromosomes. Six of these ESTs were found to map to cattle milk QTL regions. These results made it possible to assess the use of ESTs as a shortcut to the molecular identification of some QTLs and as a valuable tool for comparative mapping

The prion or the related Shadoo protein is required for early mouse embryogenesis

AbstractThe prion protein PrP has a key role in transmissible spongiform encephalopathies but its biological function remains largely unknown. Recently, a related protein, Shadoo, was discovered. Its biological properties and brain distribution partially overlap that of PrP. We report that the Shadoo-encoding gene knockdown in PrP-knockout mouse embryos results in a lethal phenotype, occurring between E8 and E11, not observed on the wild-type genetic background. It reveals that these two proteins play a shared, crucial role in mammalian embryogenesis, explaining the lack of severe phenotype in PrP-knockout mammals, an appreciable step towards deciphering the biological role of this protein family

Brain transcriptional stability upon prion protein-encoding gene invalidation in zygotic or adult mouse

<p>Abstract</p> <p>Background</p> <p>The physiological function of the prion protein remains largely elusive while its key role in prion infection has been expansively documented. To potentially assess this conundrum, we performed a comparative transcriptomic analysis of the brain of wild-type mice with that of transgenic mice invalidated at this locus either at the zygotic or at the adult stages.</p> <p>Results</p> <p>Only subtle transcriptomic differences resulting from the <it>Prnp </it>knockout could be evidenced, beside <it>Prnp </it>itself, in the analyzed adult brains following microarray analysis of 24 109 mouse genes and QPCR assessment of some of the putatively marginally modulated loci. When performed at the adult stage, neuronal <it>Prnp </it>disruption appeared to sequentially induce a response to an oxidative stress and a remodeling of the nervous system. However, these events involved only a limited number of genes, expression levels of which were only slightly modified and not always confirmed by RT-qPCR. If not, the qPCR obtained data suggested even less pronounced differences.</p> <p>Conclusions</p> <p>These results suggest that the physiological function of PrP is redundant at the adult stage or important for only a small subset of the brain cell population under classical breeding conditions. Following its early reported embryonic developmental regulation, this lack of response could also imply that PrP has a more detrimental role during mouse embryogenesis and that potential transient compensatory mechanisms have to be searched for at the time this locus becomes transcriptionally activated.</p

A novel antiangiogenic and vascular normalization therapy targeted against human CD160 receptor

A monoclonal anti-CD160 antibody inhibits the growth of new vessels in pathological ocular and tumor neoangiogenesis but not in healthy tissues

La génomique fonctionnelle de la glande mammaire des ruminants

Dans la perspective de proposer de nouveaux critères d’amélioration génétique des caractères laitiers, il est essentiel d’identifier l’ensemble des gènes ayant un effet majeur sur l’expression de ces caractères et de rechercher ensuite une éventuelle relation entre le polymorphisme de ces gènes et les performances individuelles. La caractérisation fonctionnelle des gènes transcrits dans la glande mammaire des ruminants a été entreprise, dans notre équipe, par deux approches : l’approche globale, qui permet de répertorier les gènes exprimés dans ce tissu et d’estimer leur niveau d’expression, et l’approche différentielle, qui consiste à identifier les gènes dont l’expression est spécifiquement induite par un événement (changement de stade physiologique …)

MicroRNA involvement in mammary gland development and breast cancer

MicroRNA (miRNA) are small non-coding RNA that post-transcriptionally regulate gene expression. In humans, miRNA genes may account for 2 to 3% of the total number of genes. Although the biological functions of most miRNA are unknown, their importance for development, cell proliferation, cell death, and morphogenesis has been demonstrated in several species. One could thus speculate that miRNA should be involved in the regulation of one of the organs that can undergo cycles of cell division, differentiation and dedifferentiation in the adult, the mammary gland. In this paper we summarise several reports dealing with the potential implication of miRNA in the mammary gland, most of them focussed on pathological situations, such as the appearance of breast cancer. These data suggest an implication of miRNA on mammary gland biology. However, direct evidence of this is still lacking. Expression profile analysis of miRNA during the normal mammary gland development could help in addressing this question and in identifying miRNA potentially involved. To this aim, we undertook such an analysis on mouse mammary gland at different stages (virgin, pregnancy, lactation and involution) and will present our preliminary results