- Author : Xiaoying Liang
- Publisher :
- Release : 2017
- ISBN :
- Pages : pages
Functional Characterization of a Puf Protein Family Member in Malaria Parasite Plasmodium Falciparum
Download or read book Functional Characterization of a Puf Protein Family Member in Malaria Parasite Plasmodium Falciparum written by Xiaoying Liang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Regulation of gene expression is important to cellular growth and differentiation of eukaryotes, as it plays key roles in determining the eventual expression levels and cellular localizations of a large number of proteins. RNA-binding proteins (RBPs) with conserved RNA-binding domains (RBDs) are key molecules in controlling gene expression. These conserved RBDs can specifically interact with target RNAs through specific sequences and structures to regulate mRNA stability, translation efficiency and subcellular localization. One of the well-studied RBPs is the Puf family RBPs. Members of the Puf family share a highly conserved Puf RBD, which typically consists of eight imperfect tandem repeats of ~36 amino acids (aa). Here I report the studies of two Puf members, PfPuf3 in Plasmodium falciparum and its ortholog PyPuf3 in Plasmodium yoelii. Both genes could not be disrupted, suggesting that they may be essential for the intraerythrocytic developmental cycle (IDC). A time-course study of both PfPuf3 mRNA and protein indicated that PfPuf3 was expressed during the entire IDC, with peak expression in early trophozoites. Cellular fractionation demonstrated that PfPuf3 preferentially partitioned to the nuclear than the cytoplasmic fractions. Interestingly, tagging of the endogenous of PfPuf3 and PyPuf3 with the green fluorescent protein showed that both proteins were limited to the nucleus, which is in contrast to the cytoplasmic localization of PfPuf1 and PfPuf2. Further, we found PfPuf3 co-localized with a well-known nucleolus maker PfNop1, demonstrating that PfPuf3 is a nucleolar protein. Using a parasite line with PfPuf3-tagged with PTP (ProtC-TEV-ProtA), we were able to affinity purify the PfPuf3 protein complex and the associated RNAs. Proteomic analysis of the PfPuf3 complex identified 32 proteins that are associated with the 60S ribosome subunit, suggesting that PfPuf3 might be involved in ribosomal biogenesis. RNA sequencing analysis of the purified PfPuf3 complex revealed significant enrichment of the 28S rRNA and ITS2 (internal transcribed spacer 2), implying that PfPuf3 may recognize and bind to these rRNA sequences. Taken together, these results demonstrated nucleolar localization of PfPuf3 and suggested an essential function of PfPuf3 in ribosomal biogenesis.