The skeletal muscle cell type enriched transcriptome
The main function of skeletal muscle is to provide stability, posture and movement throughout the body. It handles this by contracting and relaxing in a manner coordinated directly by impulses from the brain, i.e., it is under voluntary control, as opposed to cardiac and smooth muscle, where movement is involuntary. Another important function of skeletal muscle is to regulate body temperature. The heat is generated when the muscles contract and cause blood vessels in the skin to dilate.
1225 genes were predicted to have cell type specificity in the skeletal muscle.
Skeletal muscle cell type enriched transcriptome: Summary
Genes with predicted cell type specificity within skeletal muscle are detailed in Table 1. Identified genes are subdivided into 3 specificity categories, based on the difference between the enrichment score in the corresponding cell type, compared to the other cell types profiled in the tissue (see Methods Summary page for details):
Skeletal muscle cell type enriched transcriptome: Illustrative examples
Skeletal muscle cells consist of many individual striated muscle cells that are fused together into long, multinuclear myofibers. The contractile function of muscle cells is controlled by actin and myosin myofilaments, which form small repeating subunits known as sarcomeres which are then arranged together and aligned to form very long, repeating myofibrils, which give skeletal muscle its distinctive striated or striped pattern. Skeletal muscle myofibers can be separated into two main types, termed fast-twitch and slow-twitch.
Genes classified as having specificity in the Myocyte_1 group include the contractile protein Myosin light chain 6B (MYL6B), the regulatory protein Troponin C1, slow type (TNNC1), as well as the uncharacterized protein C12orf75, with unknown function.
Genes classified as having specificity in the Myocyte_2 group include the sarcoglycan complex subunit Sarcoglycan gamma (SGCG), which links the myocyte cytoskeleton to the extracellular matrix, as well as Calcium voltage-gated channel subunit alpha1 S (CACNA1S), involved in calcium regulation, and Protein phosphatase 1 regulatory subunit 3A (PPP1R3A), which is important for the metabolism of glycogen in muscle fibers.
Genes classified as having specificity in the Myocyte_3 group include the regulatory proteins Troponin C2, fast type (TNNC2), Myosin binding protein C2, fast isoform (MYBPC2), and ATPase sarcoplasmic/endoplasmic reticulum Ca2+ transporting 1 (ATP2A1), responsible for calcium reuptake into the sarcoplasmic reticulum.