The chemokine Sdf-1 and its receptor Cxcr4 are required for formation of muscle in zebrafish.
BACKGROUND
During development cell migration takes place prior to differentiation of many cell types. The chemokine receptor Cxcr4 and its ligand Sdf1 are implicated in migration of several cell lineages, including appendicular muscles.


RESULTS
We dissected the role of sdf1-cxcr4 during skeletal myogenesis. We demonstrated that the receptor cxcr4a is expressed in the medial-anterior part of somites, suggesting that chemokine signaling plays a role in this region of the somite. Previous reports emphasized co-operation of Sdf1a and Cxcr4b. We found that during early myogenesis Sdf1a co-operates with the second Cxcr4 of zebrafish - Cxcr4a resulting in the commitment of myoblast to form fast muscle. Disrupting this chemokine signal caused a reduction in myoD and myf5 expression and fast fiber formation. In addition, we showed that a dimerization partner of MyoD and Myf5, E12, positively regulates transcription of cxcr4a and sdf1a in contrast to that of Sonic hedgehog, which inhibited these genes through induction of expression of id2.


CONCLUSIONS
We revealed a regulatory feedback mechanism between cxcr4a-sdf1a and genes encoding myogenic regulatory factors, which is involved in differentiation of fast myofibers. This demonstrated a role of chemokine signaling during development of skeletal muscles.
Chong
Shang-Wei
SW
Laboratory of Fish Developmental Biology, Institute of Molecular and Cell Biology, Proteos, Singapore. shangwei@imcb.a-star.edu.sg <shangwei@imcb.a-star.edu.sg>
Nguyet
Le-Minh
LM
Jiang
Yun-Jin
YJ
Korzh
Vladimir
V
D000818:Animals; D002465:Cell Movement; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D024510:Muscle Development / Q000235:genetics; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology; D019718:Receptors, CXCR4 / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014158:Transcription, Genetic; D015027:Zebrafish / Q000235:genetics* / Q000254:growth & development; D029961:Zebrafish Proteins / Q000235:genetics*
D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D019718:Receptors, CXCR4; D029961:Zebrafish Proteins