Yaniv SP et al. (2012) Curr Biol "Axon regrowth during development and regeneration following injury share molecular mechanisms."

Issman-Zecharya N, Podbilewicz B, Yaniv SP, Schuldiner O, Oren-Suissa M

[Curr Biol, 2012]

BACKGROUND: The molecular mechanisms that determine axonal growth potential are poorly understood. Intrinsic growth potential decreases with age, and thus one strategy to identify molecular pathways controlling intrinsic growth potential is by studying developing young neurons. The programmed and stereotypic remodeling of Drosophila mushroom body (MB) neurons during metamorphosis offers a unique opportunity to uncover such mechanisms. Despite emerging insights into MB -neuron axon pruning, nothing is known about the ensuing axon re-extension. RESULTS: Using mosaic loss of function, we found that the nuclear receptor UNF (Nr2e3) is cell autonomously required for the re-extension of MB -axons following pruning, but not for the initial growth or guidance of any MB neuron type. We found that UNF promotes this process of developmental axon regrowth via the TOR pathway as well as a late axon guidance program via an unknown mechanism. We have thus uncovered a novel developmental program of axon regrowth that is cell autonomously regulated by the UNF nuclear receptor and the TOR pathway. CONCLUSIONS: Our results suggest that UNF activates neuronal re-extension during development. Taken together, we show that axon growth during developmental remodeling is mechanistically distinct from initial axon outgrowth. Due to the involvement of the TOR pathway in axon regeneration following injury, our results also suggests that developmental regrowth shares common molecular mechanisms with regeneration following injury.

trimethylamine monooxygenase activity

Catalysis of the reaction: N,N,N-trimethylamine + NADPH + H+ + O2 = N,N,N-trimethylamine N-oxide + NADP+ + H2O.

obsolete ubiquitin-calmodulin ligase activity

OBSOLETE. Catalysis of the reaction: n ATP + calmodulin + n ubiquitin = n AMP + n diphosphate + ubiquitin(n)-calmodulin.

N,N-dimethylaniline monooxygenase activity

Catalysis of the reaction: N,N-dimethylaniline + NADPH + H+ + O2 = N,N-dimethylaniline N-oxide + NADP+ + H2O.

dimethylaniline-N-oxide aldolase activity

Catalysis of the reaction: N,N-dimethylaniline N-oxide = N-methylaniline + formaldehyde.

alpha-glucan, water dikinase activity

Catalysis of the reaction: [(1->4)-alpha-D-glucosyl](n) + n ATP + n H2O = [(1->4)-6-phospho-alpha-D-glucosyl](n) + n AMP + 2n H+ + n phosphate.

trimethyllysine dioxygenase activity

Catalysis of the reaction: 2-oxoglutarate + N(6),N(6),N(6)-trimethyl-L-lysine + O2 = 3-hydroxy-N(6),N(6),N(6)-trimethyl-L-lysine + CO2 + succinate.

N',N'',N'''-triacetylfusarinine C metabolic process

The chemical reactions and pathways involving N',N'',N'''-triacetylfusarinine C.

obsolete N,N'-diacetylchitobiose synthase activity

OBSOLETE. Catalysis of the reaction: n H2O + chitin = N,N'-diacetylchitobiose.

N-terminal peptidyl-serine trimethylation

The trimethylation of the N-terminal serine of proteins to form the derivative N,N,N-trimethylserine.