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Cloning, gene regulation, and neuronal proliferation functions of novel N‐terminal–truncated carboxypeptidase E/neurotrophic factor‐αl variants in embryonic mouse brain
Author(s) -
Xiao Lan,
Yang Xuyu,
Sharma Vinay Kumar,
Loh Y. Peng
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201800359r
Subject(s) - biology , embryonic stem cell , microbiology and biotechnology , neurotrophic factors , neurogenesis , gene , genetics , receptor
Carboxypeptidase E (CPE), an exopeptidase involved in proneuropeptide processing, is also a neurotrophic factor, named neurotrophic factor‐α1 (NF‐α1) and has important roles in neuroprotection, stem cell differentiation, and neurite outgrowth, independent of enzymatic activity. Additionally, an N‐terminal–truncated CPE/NF‐α1 variant, (CPE/NF‐α1)‐ΔN, proposed from bioinformatic analysis of GenBank (National Center for Biotechnology Information, Bethesda, MD, USA) DNA sequences and encoding a 40‐kDa protein, has been found to be exclusively expressed in embryonic neurons. To investigate the function of (CPEZNF‐α1)‐ΔN in neurodevelopment, we first cloned (CPEZNF‐α1)‐ΔN transcripts from an embryonic mouse brain. A rapid amplification of cDNA ends assay, DNA sequencing, and Northern blot revealed 1.9‐ and 1.73‐kb transcripts, which encoded 47‐ and 40‐kDa (CPE/NF‐α1)‐ΔN proteins, respectively. Those proteins were expressed in embryonic mouse brain. Expression of the 2 (CPE/NF‐α1)‐ΔN mRNAs surged at embryonic d 10.5, correlating with the time of neurogenesis in the developing brain and also at postnatal d 1. HT22 cells, a mouse hippocampal cell line, transduced with 40 kDa (CPE/NF‐α1)‐ΔN up‐regulated expression of genes involved in embryonic neurodevelopment: insulin‐like growth factor binding protein 2 ( IGFBP2 ), death‐associated protein 1, and ephrin A1, which regulate proliferation, programmed cell death, and neuronal migration, respectively. HT22 cells and embryonic cortical neurons overexpressing 40 kDa (CPE/NF‐α1)‐ΔN exhibited enhanced proliferation, which was inhibited by IGFBP2 short interfering RNA treatment. Thus, 40 kDa (CPE/NF‐α1)‐ΔN has an important, enzymatically independent role in the regulation of genes critical for neurodevelopment.—Xiao, L., Yang, X., Sharma, V. K., Loh, Y. P. Cloning, gene regulation, and neuronal proliferation functions of novel N‐terminal–truncated carboxypeptidase E/neurotrophic factor‐α1 variants in embryonic mouse brain. FASEB J. 33, 808–820 (2019). www.fasebj.org