Utilization of Host SR Protein Kinases and RNA-Splicing Machinery during Viral Replication

• Published in: Proceedings of the National Academy of Sciences - PNAS 2006-07, Vol.103 (30), p.11329-11333
• Main Authors: Fukuhara, Takeshi, Hosoya, Takamitsu, Shimizu, Saki, Sumi, Kengo, Oshiro, Takako, Yoshinaka, Yoshiyuki, Suzuki, Masaaki, Yamamoto, Naoki, Herzenberg, Leonore A., Herzenberg, Leonard A., Hagiwara, Masatoshi
• Format: Article
• Language: English
• Subjects: Biological Sciences; Cell Line; Cell lines; Cells; Down-Regulation; Enzymes; Gene Expression Regulation, Viral; Genome, Viral; Genomics; HEK293 cells; HIV; HIV - genetics; HIV 1; Human immunodeficiency virus; Humans; Kinetics; Phosphorylation; Plasmids - metabolism; Proteins; Ribonucleic acid; RNA; RNA Splicing; RNA-Binding Proteins - metabolism; RNA-Binding Proteins - physiology; Sindbis Virus; Sindbis Virus - metabolism; Splicing; Up-Regulation; Virus Replication; Viruses
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0604616103

Although the viral genome is often quite small, it encodes a broad series of proteins. The virus takes advantage of the host-RNA-processing machinery to provide the alternative splicing capability necessary for the expression of this proteomic diversity. Serinearginine-rich (SR) proteins and the kinases that activate them are central to this alternative splicing machinery. In studies reported here, we use the HIV genome as a model. We show that HIV expression decreases overall SR protein/activity. However, we also show that HIV expression is significantly increased (20-fold) when one of the SR proteins, SRp75 is phosphorylated by SR protein kinase (SRPK)2. Thus, inhibitors of SRPK2 and perhaps of functionally related kinases, such as SRPK1, could be useful antiviral agents. Here, we develop this hypothesis and show that HIV expression down-regulates SR proteins in Flp-In293 cells, resulting in only low-level HIV expression in these cells. However, increasing SRPK2 function up-regulates HIV expression. In addition, we introduce SR protein phosphorylation inhibitor 340 (SRPIN340), which preferentially inhibits SRPK1 and SRPK2 and down-regulates SRp75. Although an isonicotinamide compound, SPRIN340 (or its derivatives) remain to be optimized for better specificity and lower cytotoxicity, we show here that SRPIN340 suppresses propagation of Sindbis virus in plaque assay and variably suppresses HIV production. Thus, we show that SRPK, a well known kinase in the cellular RNA-processing machinery, is used by at least some viruses for propagation and hence suggest that SRPIN340 or its derivatives may be useful for curbing viral diseases.