FERM domain containing protein 7 (FRMD7) upregulates the expression of neuronal cytoskeletal proteins and promotes neurite outgrowth in Neuro-2a cells.
OBJECTIVE
Mutations of the FERM domain containing protein 7 gene (FRMD7) are associated with X-linked idiopathic congenital nystagmus. Previous studies have shown that FRMD7 plays an important role in neuronal development and is involved in the regulation of F-actin. However, its specific mechanism of action remains undetermined.


METHODS
Our study used quantitative real-time PCR to assess the levels of neuron-specific genes in a mouse neuroblastoma cell line (Neuro-2a) after transfection with a full-length coding transcript of FRMD7 or a blank control vector. F-actin was detected by rhodamine-phalloidin staining. Neurite number and length were assessed by a confocal laser scanning microscope.


RESULTS
We demonstrated that FRMD7 can promote neurite outgrowth following retinoic acid-induced differentiation in Neuro-2a cells. Neurites were significantly longer in cells transfected with FRMD7, but there was no difference in cell numbers. The mRNA expression of neuron cytoskeletal-related genes (microtubule-associated protein 2 [Mtap2], neurofilament-L and M [NF-L and NF-M] and the microtubule-associated protein tau [MAPT]) were significantly increased compared to controls. Other genes (NF-H, MAPT, neuron-specific class III beta-tubulin (Tuj-1), nestin, and growth-associated protein-43 [GAP-43]) were not obviously altered by FRMD7 overexpression.


CONCLUSIONS
Taken together, our data suggest that FRMD7 promotes the extension of neurites and may be involved in regulating the movement of cytoskeletal proteins, which influences not only F-actin, but also NF and microtubule dynamics.
Department of Neurology, second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
Jiali
J
Pu
Xiaoxiong
X
Lu
Guohua
G
Zhao
Yaping
Y
Yan
Jun
J
Tian
Baorong
B
Zhang
D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002452:Cell Count; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D003598:Cytoskeletal Proteins; D019922:GAP-43 Protein / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000235:genetics* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D064231:Nestin; D016501:Neurites / Q000378:metabolism*; D009447:Neuroblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016900:Neurofilament Proteins / Q000235:genetics / Q000378:metabolism; D010957:Plasmids; D021381:Protein Transport / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology; D014404:Tubulin / Q000235:genetics / Q000378:metabolism; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism
D000199:Actins; D003598:Cytoskeletal Proteins; C547741:FRMD7 protein, mouse; D019922:GAP-43 Protein; D007381:Intermediate Filament Proteins; C558298:Mapt protein, mouse; D008869:Microtubule-Associated Proteins; C079240:Mtap2 protein, mouse; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; D064231:Nestin; D016900:Neurofilament Proteins; D012333:RNA, Messenger; D014404:Tubulin; C462941:beta3 tubulin, mouse; D016875:tau Proteins; D014212:Tretinoin