This report describes fly models relevant to myopathies that are FLNC-related. The human gene implicated in these diseases is filamin C (FLNC), a muscle-specific filamin associated with the sarcomeric Z disk. FLNC is implicated in several forms of myopathy, 'myopathy, myofibrillar, 5' (MIM:609524, FBhh0000672), 'cardiomyopathy, familial hypertrophic 26' (MIM:617047, FBhh0000671) and 'myopathy, distal, 4' (MIM:614065, FBhh0000673); all are inherited as autosomal dominants. There is a single orthologous gene in Drosophila, cher, for which classical loss-of-function alleles, RNAi-targeting constructs, and alleles caused by insertional mutagenesis have been generated. Dmel\cher is also orthologous to the human genes FLNA and FLNB.
The human FLNC gene has not been introduced into flies.
Since expression of cher is not restricted to muscle, a number of phenotypes observed for cher mutations are not related to muscle. Animals homozygous for an amorphic allele of Dmel\cher are viable; females are sterile. RNAi-effected loss of cher in muscle results in a decrease in adult viability, a flightless phenotype, and severe sarcomere phenotypes. Physical and genetic interactions of Dmel\cher have been described; see below and in the cher gene report.
[updated Dec. 2017 by FlyBase; FBrf0222196]
One of a group of 'Z-disk diseases' that typically manifests as distal myopathy, but may also affect proximal muscles and the heart (Selcen and Carpen, 2008; pubmed:19181098).
The morphological findings are typical of myofibrillar myopathy (MFM) and include Z-disk alterations and aggregation of dense filamentous material visible in trichrome staining(Selcen and Carpen, 2008; pubmed:19181098).
FLNC is muscle-specific filamin; filamin proteins crosslink actin filaments into orthogonal networks in cortical cytoplasm and participate in the anchoring of membrane proteins for the actin cytoskeleton. FLNC is critical for normal myogenesis and for maintaining the structural integrity of the muscle fibers; may also display structural functions at the Z lines in muscle cells. [from Gene Cards, FLNC; 2017.12.01]
Many to one (3 human to 1 Drosophila); the other human genes are FLNA and FLNB.
Moderate- to high-scoring ortholog of human FLNA, FLNC, and FLNB (1 Drosophila to 3 human); Dmel\cher shares 45-46% identity and 59-61% similarity with the human genes.