Long-lasting alternative splicing of neuronal acetylcholinesterase (AChE) pre-mRNA occurs during neuronal development and following stress, altering synaptic properties. To explore the corresponding molecular events, we sought to identify mRNAs encoding for abundant splicing factors in the prefrontal cortex (PFC) following stress. Here we show elevated levels of the splicing factor SC35 in stressed as compared with naïve mice. In cotransfections of COS-1 and HEK293 cells with an AChE minigene allowing 3′ splice variations, SC35 facilitated a shift from the primary AChE-S to the stress-induced AChE-R variant, while ASF/SF2 caused the opposite effect. Transfection with chimeric constructs comprising of SC35 and ASF/SF2 RRM/RS domains identified the SC35 RRM as responsible for AChE mRNA's alternative splicing. In poststress PFC neurons, increased SC35 mRNA and protein levels coincided with selective increase in AChE-R mRNA. In the developing mouse embryo, cortical progenitor cells in the ventricular zone displayed transient SC35 elevation concomitant with dominance of AChE-R over AChE-S mRNA. Finally, transgenic mice overexpressing human AChE-R, but not those overexpressing AChE-S, showed significant elevation in neuronal SC35 levels, suggesting a reciprocal reinforcement process. Together, these findings point to an interactive relationship of SC35 with cholinergic signals in the long-lasting consequences of stress on nervous system plasticity and development.
Bibliographical noteFunding Information:
We thank Dr Javier Caceres (Edinburgh) for kindly providing SC35 plasmids and Dr Bat-Sheva Kerem (Jerusalem) for SRp20 and ASF/SF2 plasmids. This study was supported by the Israel Science Fund (618/ 02-1), the European Union (QLK3-CT-2002-02062, LSHM-CT-2003-503330, DIP-G-3.2) and EURASNET, the Israel–US Binational Industrial Research and Development (BIRD-F) to Ester Neurosciences Ltd (www.esterneuro.com) and Pharmacopeia, Inc. EM has been an incumbent of a Lionel Perez predoctoral fellowship from the Israel Interdisciplinary Center for Neural Computation, the Hebrew University Rector’s doctoral fellowship and a Golda Meir fellowship. BB has been an incumbent of a Haselkorn Fellowship. AD has been an incumbent of a postdoctoral fellowship from the Israel Psychobiology Fund.
- Alternative splicing