Fast-twitch myofibrils grow in proportion to Mylpf dosage in the zebrafish embryo.

ABSTRACT: Muscle cells become stronger by expanding myofibrils, the chains of sarcomeres that produce contraction. Here we investigate how Mylpf (Myosin Light Chain Phosphorylatable Fast) abundance impacts myofibril assembly in fast-twitch muscle. The two zebrafish Mylpf genes (mylpfa and mylpfb) are exclusively expressed in fast-twitch muscle. We show that these cells initially produce six times more mylpfa mRNA and protein than mylpfb. The combined Mylpf protein dosage is necessary for and proportionate to fast-twitch myofibril growth in the embryo. Fast-twitch myofibrils are severely reduced in the mylpfa ^-/- mutant, leading to loss of high-speed movement; however, by persistent slow movement this mutant swims as far through time as its wild-ty

SUBMITTER: Adekeye TE 

PROVIDER: S-EPMC11429778 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature