The LIM domain protein FHL1 (SLIM 1) transcript is preferentially expressed in postnatal skeletal muscle but almost nothing is known about its function in this tissue. In this study we have examined the expression of the FHL1 transcript at the cellular level by in situ hybridisation. Muscle fibers exist as a number of discrete subpopulations or "types" which are differentiated by their contractile and metabolic properties. It was observed that the FHL1 transcript was not fiber-type specific but was however more abundant in oxidative fibers. Muscle atrophy induced by disuse caused a significant decline in the expression of the transcript but atrophy induced by short-term denervation did not. Hypertrophy of skeletal muscle induced by passive stretch was associated with an up-regulation of the FHL1 transcript. These data are consistent that FHL1 is involved in synthetic processes within the muscle fibre.
Copyright 2000 Academic Press.