Schwerin M., Czernek-Schäfer D., Goldammer T., Kata S.R., Womack James E., Pareek R.S., Walawski K., Brunner R.M..
2002. Disease-associated differentially expressed genes. Mining for functional candidate genes for mastitis resistance in cattle.
In : Second international symposium on Candidate Genes for Animal Health (C.G.A.H), Montpellier, France, August 16-18th 2002 : abstracts. CIRAD, INRA
Note générale : Session 1 : Present and future strategies and tools of the candidate gene approach
Résumé : In the last 5 years many experiments have identified a high number of different QTL regions in cattle affecting milk performance, growth, meat quality, exterior, but also functional traits as mastitis resistance, conformation traits and stayability. QTL positions, and highly significant QTL effects repeatedly confirmed in independent studies emphasize the potential value of mapped QTL for marker-assisted selection programmes. Efficient utilization of mapped QTLs requires a higher mapping resolution. However, a higher resolution map, only partly resolves the problem for efficient application of genetic markers in selection programs. The ultimate target of QTL analysis beyond fine mapping is the identification of the gene itself. One of the major efforts in this sense is the identification of coding sequences or transcript units, especially those that are localized in the QTL region of interest and that are trait-associated expressed. In this study the mRNA differential display method was applied to identify mastitis-associated expressed DNA sequences based on different expression patterns in the mammary gland by comparative analysis of non-infected and infected udder quarters of a cow. In total 704 different cDNA bands were displayed in both udder samples. Of these bands 532 (75.6%) were differentially displayed. Of these prominent cDNA bands were isolated, reamplified, cloned and sequenced. Ninety expressed sequence tags (EST) were identified and characterized. Database search showed that 18 ESTs were similar to previously described genes. Additionally, 18 ESTs showed similarity with ESTs of database and 32 ESTs did not match with any database entries. The rest were similar to repetitive, BAC, PAC or rRNA sequences. Of the ESTs showing similarity with previously described genes the majority (>40%) exhibited homology to genes involved in cellular signal transfer, whereas about 10% showed homology to genes involved in cellular immune response. In a combined approach these sequences were proved (1) for their mastitis-associated expression in a representative number of udder samples of animals with and without clinical mastitis by quantitative RT-PCR using LightCycler®, (2) for their epithelium specific expression in the mammary gland by tissue in situ hybridization, and (3) physically mapped by radiation hybrid mapping to develop and to integrate them into a combined marker/gene map especially considering QTL regions of interest. According to their localization in a QTL region based on generated chromosome specific combined marker/gene-maps and to their diseaseassociated expression potential candidate genes (e. g. PLAUR, SSR1, RSC1A1) potentially involved in mastitis resistance were identified. These results clearly show that the combination of positional and functional candidate gene approaches represents a helpful prerequisite for ultimate cloning of candidate genes underlying QTL effects. (Texte intégral)
Mots-clés Agrovoc : expression des gènes, maladie des animaux, résistance aux maladies, biologie moléculaire
Classification Agris : L10 - Génétique et amélioration des animaux
Auteurs et affiliations
- Schwerin M., Research Institute for the Biology of Farm Animals (DEU)
- Czernek-Schäfer D., Research Institute for the Biology of Farm Animals (DEU)
- Goldammer T., Research Institute for the Biology of Farm Animals (DEU)
- Kata S.R., Texas A & M University (USA)
- Womack James E., Texas A & M University (USA)
- Pareek R.S., University of Warmia and Mazury (POL)
- Walawski K., University of Warmia and Mazury (POL)
- Brunner R.M., Research Institute for the Biology of Farm Animals (DEU)
Autres liens de la publication
Source : Cirad - Agritrop (https://agritrop.cirad.fr/512010/)
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