Anti-Fkrp polyclonal antibody

Purpose: Dystroglycanopathies are a heterogeneous group of recessive neuromuscular dystrophies that affect the muscle, brain and retina, and are caused by deficiencies in the O-glycosylation of a-dystroglycan. This post-translational modification is essential for the formation and maintenance of ribbon synapses in the retina. Fukutin and fukutin-related protein (FKRP) are two glycosyltransferases whose deficiency is associated with severe dystroglycanopathies. These enzymes carry out in vitro the addition of a tandem ribitol 5-phosphate moiety to the so-called core M3 phosphotrisaccharide of a-dystroglycan. However, their expression pattern and function in the healthy mammalian retina has not so far been investigated. In this work, we have addressed the expression of the FKTN (fukutin) and FKRP genes in the retina of mammals, and characterized the distribution pattern of their protein products in the adult mouse retina and the 661W photoreceptor cell line. Methods: By means of reverse transcription (RT)-PCR and immunoblotting, we have studied the expression at the mRNA and protein levels of the fukutin and FKRP genes in different mammalian species, from rodents to humans. Immunofluorescence confocal microscopy analyses were performed to characterize the distribution profile of their protein products in mouse retinal sections and in 661W cultured cells. Results: Both genes were expressed at the mRNA and protein levels in the neural retina of all mammals studied. Fukutin was present in the cytoplasmic and nuclear fractions in the mouse retina and 661W cells, and accumulated in the endoplasmic reticulum. FKRP was located in the cytoplasmic fraction in the mouse retina and concentrated in the Golgi complex. However, and in contrast to retinal tissue, FKRP additionally accumulated in the nucleus of the 661W photoreceptors. Conclusions: Our results suggest that fukutin and FKRP not only participate in the synthesis of O-mannosyl glycans added to alpha-dystroglycan in the endoplasmic reticulum and Golgi complex, but that they could also play a role, that remains to be established, in the nucleus of retinal neurons.

Walker-Warburg syndrome (WWS) is a rare autosomal recessive disorder characterized by congenital muscular dystrophy (CMD) and brain and eye abnormalities. Two other diseases have similar features, namely, muscle-eye-brain disease (MED) and Fukuyama congenital muscular dystrophy (FCMD). The brain abnormalities in WWS are characterized by type 2 cobblestone lissencephaly, hydrocephalus, cerebellar malformations and brain stem anomalies. Mutations in protein O-mannosyltransferase 1 and 2 (POMT1 and POMT2) genes were found in 20% of WWS cases. Other rare mutations were found in Fukutin and Fukutin-related protein (FKRP) genes. We report cases of two Kuwaiti boys with WWS, who had typical brain magnetic resonance imaging (MRI) features. Both were screened for POMT1, POMT2, POMGnT1, FKRP and LARGE gene mutations and were negative. To the best of our knowledge these are the first two cases to be screened for known WWS gene mutations in Kuwait.