Expression of DNAJA1 in bovine muscles according to developmental age and management factors.

We have recently shown that the expression of the DNAJA1 gene encoding a heat shock protein (Hsp40) is a negative marker of meat tenderness in Charolais bulls. To acquire knowledge on the regulation of DNAJA1 expression, we analysed the abundance of DNAJA1 transcripts and protein during development and according to management factors (e.g. feeding treatments, growth path and stress status) in different bovine muscles during postnatal life. We report here a developmental expression profile for DNAJA1 with decreased levels of transcript and protein during the progression of myogenesis. During postnatal life, we found the highest expression of DNAJA1 in the most oxidative muscles. No effect was detected for dietary treatment (pasture v. maize-based diet), growth path (compensatory growth after a restriction period) or pre-slaughter stress status. Therefore, the genetic background and muscle type could be considered as the main factors regarding the level of DNAJA1. Integration of the knowledge gained from this study should help to predict muscle metabolic properties and the ability of the live animals to give high sensory quality meat.