5' and 3' end modifications of spliceosomal RNAs in Plasmodium falciparum.
5' caps provide recognition sequences for the nuclear import of snRNAs. The 5' and 3' ends of snRNAs were studied in Plasmodium falciparum with a modified adapter ligation method, which showed that 5' ends of U1, U2, U4, U5 and U6 snRNAs are capped. In P. falciparum, the 3' ends of U1, U2, U4 and U5 snRNAs have free hydroxyl groups whereas U6 snRNA has a blocked 3' end. An immunoprecipitation assay for trimethyl guanosine caps shows that the cap structures of parasite U1-U5 snRNAs are hypermethylated while U6 snRNA may be gamma-mono-methylated. Bioinformatics analysis of proteins involved in hypermethylation and trafficking of snRNAs indicates that the methyltransferase TGS1 is present in the P. falciparum genome. PfTGS1 is larger than its orthologs and may have transmembrane domains in the C-terminus. Surprisingly, the snRNA trafficking protein Snurportin is absent from the P. falciparum genome suggesting that reminiscent of yeast, parasite snRNAs may be retained in the nucleus.
Bawankar
Praveen
P
School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400072, India.
Shaw
Philip J
PJ
Sardana
Richa
R
Babar
Prasad H
PH
Patankar
Swati
S
D000818:Animals; D015152:Blotting, Northern; D030541:Databases, Genetic; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008018:Life Cycle Stages; D008780:Methyltransferases / Q000378:metabolism; D010963:Plasmodium falciparum / Q000166:cytology* / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D012323:RNA Processing, Post-Transcriptional; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism*; D012342:RNA, Small Nuclear / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D017381:Spliceosomes / Q000235:genetics*
D016053:RNA, Protozoan; D012342:RNA, Small Nuclear; D008780:Methyltransferases; C456271:trimethylguanosine synthase