High impact information on RAT1

• We discuss the possible significance of the Rat1p/Sep1p homology for RNA trafficking [1].
• Isolation and characterization of RAT1: an essential gene of Saccharomyces cerevisiae required for the efficient nucleocytoplasmic trafficking of mRNA [1].
• Chromatin immunoprecipitation experiments show that polyadenylation factors and Rat1 localize to snoRNA genes, but mutations that disrupt poly(A) site cleavage or Rat1 activity do not lead to termination defects at these genes [2].
• Thus, the XRN-family in plants is more complex than in other eukaryotes, and, if an XRN-like enzyme plays a role in mRNA decay in plants, the likely participant is a cytoplasmic Xrn2p/Rat1p ortholog, rather than an Xrn1p ortholog [3].
• First, the Arabidopsis genome contains three XRN-like genes (AtXRNs) that are structurally similar to Xrn2p/Rat1p, a characteristic unique to plants [3].

Biological context of RAT1

• The RAT1 gene of Saccharomyces cerevisiae encodes a 5'-->3' exoribonuclease which plays an essential role in yeast RNA degradation and/or processing in the nucleus [4].
• Polysome analysis of an rai1 deletion mutant indicated a defect in 60S biogenesis which was nearly fully reversed by high-copy RAT1 [4].
• Sporulation of heterozygous HKE1/hke1::URA3 diploids reveals that this gene, unlike the highly related XRN1/KEM1 gene, is essential for cell viability [5].
• We identified two such mutations in the same gene, which we named TAP1 (for transcription activation protein) [6].
• Both the level of this protein and the RNase activity correlate with HKE1 gene dosage [5].

Anatomical context of RAT1

• Immunodetection analyses with enriched fractions of chloroplast proteins indicated that Rat1 is associated with chloroplast membranes [7].

Associations of RAT1 with chemical compounds

• Finally, we found that the treatment of RAT1 cell extracts with N-ethylmaleimide leads to a loss of the major PRMT1-associated activity that was immune to inhibition under the same conditions as a GST fusion protein [8].
• However, rat PRMT1 and PRMT3 glutathione S-transferase fusion proteins have distinct enzyme specificities for substrates present in both hypomethylated rmt1 yeast extract and hypomethylated RAT1 embryo cell extract [9].

Other interactions of RAT1

• Sequence data are presented for the Saccharomyces cerevisiae TAP1 gene and for a mutant allele, tap1-1, that activates transcription of the promoter-defective yeast SUP4 tRNA(Tyr) allele SUP4A53T61 [10].
• Processing of the polycistronic precursor requires nucleases also involved in rRNA processing, i.e., Rnt1p and Rat1p [11].
• Seven novel methylation guide small nucleolar RNAs are processed from a common polycistronic transcript by Rat1p and RNase III in yeast [11].

Analytical, diagnostic and therapeutic context of RAT1

• Immunofluorescence analysis localized PRMT1 predominantly to the nucleus of RAT1 cells [9].

References