Characterization of follistatin-related gene as a negative regulatory factor for activin family members during mouse heart development.
Follistatin-related gene (FLRG) encodes a secretory glycoprotein that has characteristic cysteine-rich follistatin domains. FLRG protein binds to and neutralizes several transforming growth factor-beta (TGF-beta) superfamily members, including myostatin (MSTN), which is a potent negative regulator of skeletal muscle mass. We have previously reported that FLRG was abundantly expressed in fetal and adult mouse heart. In this study, we analyzed the expression of FLRG mRNA during mouse heart development. FLRG mRNA was continuously expressed in the embryonic heart, whereas it was very low in skeletal muscles. By contrast, MSTN mRNA was highly expressed in embryonic skeletal muscles, whereas the expression of MSTN mRNA was rather low in the heart. In situ hybridization and immunohistochemical analysis revealed that FLRG expressed in smooth muscle of the aorta and pulmonary artery, valve leaflets of mitral and tricuspid valves, and cardiac muscles in the ventricle of mouse embryonic heart. However, MSTN was expressed in very limited areas, such as valve leaflets of pulmonary and aortic valves, the top of the ventricular and atrial septa. Interestingly, the expression of MSTN was complementary to that of FLRG, especially in the valvular apparatus. Biochemical analyses with surface plasmon resonance biosensor and reporter assays demonstrated that FLRG hardly dissociates from MSTN and activin once it bound to them, and efficiently inhibits these activities. Our results suggest that FLRG could function as a negative regulator of activin family members including MSTN during heart development.
Takehara-Kasamatsu
Yuka
Y
Institute for Enzyme Research, The University of Tokushima, Tokushima, Japan.
Tsuchida
Kunihiro
K
Nakatani
Masashi
M
Murakami
Tatsuya
T
Kurisaki
Akira
A
Hashimoto
Osamu
O
Ohuchi
Hideyo
H
Kurose
Hitomi
H
Mori
Kazuhiro
K
Kagami
Shoji
S
Noji
Sumihare
S
Sugino
Hiromu
H
D028341:Activins / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005318:Fetal Heart / Q000196:embryology / Q000378:metabolism*; D038702:Follistatin-Related Proteins; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D008813:Mice, Inbred ICR; D055435:Myostatin; D011247:Pregnancy; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism
D017931:DNA Primers; D038702:Follistatin-Related Proteins; C498620:Fstl3 protein, mouse; C525912:Mstn protein, mouse; D055435:Myostatin; D011506:Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D028341:Activins