Effect of thymosin beta15 on the branching of developing neurons.
The thymosin betas (Tbetas) are polypeptide regulators of actin dynamics that are critical for the growth and branching of neurites in developing neurons. We found that mRNAs for Tbeta4, Tbeta10, and Tbeta15 were highly expressed in the developing rat brain during neuritogenesis, supporting a role for the Tbetas in this process. Overexpression of the Tbetas increased the number of neurite branches per neuron in cultured hippocampal and cerebral cortex neurons, and Tbeta15 had the greatest effect. Actin binding activity appears to be essential for the branch-promoting activity of Tbetas because two mutants of Tbeta15 lacking monomeric actin binding activity failed to stimulate branch formation. We also found that transfection of siRNA against Tbeta15 reduced branching. Taken together, these data suggest that the three Tbetas, and especially Tbeta15, stimulate neurite branching during brain development.
Choe
Jeehyung
J
Department of Anatomy and Division of Brain Korea 21 Biomedical Science, Korea University College of Medicine, 126-1, 5-Ka, Anam-Dong, Sungbuk-Gu, Seoul 136-705, Republic of Korea.
Sun
Woong
W
Yoon
Seung-Yong
SY
Rhyu
Im Joo
IJ
Kim
Eun Hae
EH
Kim
Hyun
H
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000166:cytology / Q000196:embryology*; D002478:Cells, Cultured; D008969:Molecular Sequence Data; D016501:Neurites / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013947:Thymosin / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000502:physiology*
D000199:Actins; C525161:thymosin beta15, rat; D013947:Thymosin