title: CMP‑N‑acetylneuraminic acid synthetase interacts with fragile X related protein 1.
abstract: Fragile X mental retardation protein (FMRP), fragile X related 1 protein (FXR1P) and FXR2P are the members of the FMR protein family. These proteins contain two KH domains and a RGG box, which are characteristic of RNA binding proteins. The absence of FMRP, causes fragile X syndrome (FXS), the leading cause of hereditary mental retardation. FXR1P is expressed throughout the body and important for normal muscle development, and its absence causes cardiac abnormality. To investigate the functions of FXR1P, a screen was performed to identify FXR1P‑interacting proteins and determine the biological effect of the interaction. The current study identified CMP‑N‑acetylneuraminic acid synthetase (CMAS) as an interacting protein using the yeast two‑hybrid system, and the interaction between FXR1P and CMAS was validated in yeast using a β‑galactosidase assay and growth studies with selective media. Furthermore, co‑immunoprecipitation was used to analyze the FXR1P/CMAS association and immunofluorescence microscopy was performed to detect expression and intracellular localization of the proteins. The results of the current study indicated that FXR1P and CMAS interact, and colocalize in the cytoplasm and the nucleus of HEK293T and HeLa cells. Accordingly, a fragile X related 1 (FXR1) gene overexpression vector was constructed to investigate the effect of FXR1 overexpression on the level of monosialotetrahexosylganglioside 1 (GM1). The results of the current study suggested that FXR1P is a tissue‑specific regulator of GM1 levels in SH‑SY5Y cells, but not in HEK293T cells. Taken together, the results initially indicate that FXR1P interacts with CMAS, and that FXR1P may enhance the activation of sialic acid via interaction with CMAS, and increase GM1 levels to affect the development of the nervous system, thus providing evidence for further research into the pathogenesis of FXS.
authors.affiliation: Department of Biochemistry & Biology, University of South China, Hengyang, Hunan 421001, P.R. China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Biochemistry & Biology, University of South China, Hengyang, Hunan 421001, P.R. China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Tian
authors.affiliation: Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmaceutical and Biological Sciences, University of South China, Hengyang, Hunan 421001, P.R. China.
authors.forename: Zongbao
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Biochemistry & Biology, University of South China, Hengyang, Hunan 421001, P.R. China.
authors.forename: Changbo
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Biochemistry & Biology, University of South China, Hengyang, Hunan 421001, P.R. China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Biochemistry & Biology, University of South China, Hengyang, Hunan 421001, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Biochemistry & Biology, University of South China, Hengyang, Hunan 421001, P.R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Biochemistry & Biology, University of South China, Hengyang, Hunan 421001, P.R. China.
authors.forename: Shuya
authors.initials: S
authors.lastname: He
mesh_terms: D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005600:Fragile X Syndrome / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D000216:N-Acylneuraminate Cytidylyltransferase / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D021381:Protein Transport; D020798:Two-Hybrid System Techniques
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; D000216:N-Acylneuraminate Cytidylyltransferase; D009844:Oligosaccharides; C497683:FMR1 protein, human; C519498:GM1 pentasaccharide