Poly C binding protein 1 (PCBP) is involved in the transcriptional regulation of neuronal mu-opioid receptor gene. In this study, we examined the molecular basis of PCBP cellular/nuclear localization in neuronal cells using EGFP fusion protein. PCBP, containing three KH domains and a variable domain, distributed in cytoplasm and nucleus with a preferential nuclear expression. Domain-deletional analyses suggested the requirement of variable and KH3 domains for strong PCBP nuclear expression. Within the nucleus, a low nucleolar PCBP expression was observed, and PCBP variable domain contributed to this restricted nucleolar expression. Furthermore, the punctate nuclear pattern of PCBP was correlated to its single-stranded (ss) DNA binding ability, with both requiring cooperativity of at least three sequential domains. Collectively, certain PCBP domains thus govern its nuclear distribution and transcriptional regulatory activity in the nucleus of neurons, whereas the low nucleolar expression implicates the disengagement of PCBP in the ribosomal RNA synthesis.
|Original language||English (US)|
|Number of pages||9|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Nov 3 2006|
Bibliographical noteFunding Information:
We thank Dr. Joshua Berlin for the use of the confocal microscope in the beginning of early experiments. The acquisition of Fluoview 1000 confocal microscope is supported by the MRI Grant of NSF. We thank Drs. Linda Hsu, Hsien-Ching Liu, and Andrew P. Smith for their intellectual contributions and helping in preparation of the manuscript. This research was supported by NIH research Grant DA-016673.
- A punctate nuclear pattern
- Cellular expression
- KH domains and variable domain
- Neuronal cells
- Nucleolar and nucleoplasmic regions
- Poly C binding protein 1