SummaryWe have produced 22 090 primary transgenic rice plants that carry a T-DNA insertion, which has resulted in 18 358 fertile lines. Genomic DNA gel-blot and PCR analyses have shown that approximately 65% of the population contains more than one copy of the inserted T-DNA. Hygromycin resistance tests revealed that transgenic plants contain an average of 1.4 loci of T-DNA inserts. Therefore, it can be estimated that approximately 25 700 taggings have been generated. The binary vector used in the insertion contained the promoterless b-glucuronidase (GUS) reporter gene with an intron and multiple splicing donors and acceptors immediately next to the right border. Therefore, this gene trap vector is able to detect a gene fusion between GUS and an endogenous gene, which is tagged by T-DNA. Histochemical GUS assays were carried out in the leaves and roots from 5353 lines, mature¯owers from 7026 lines, and developing seeds from 1948 lines. The data revealed that 1.6±2.1% of tested organs were GUS-positive in the tested organs, and that their GUS expression patterns were organ-or tissue-speci®c or ubiquitous in all parts of the plant. The large population of T-DNA-tagged lines will be useful for identifying insertional mutants in various genes and for discovering new genes in rice.

No abstract

Testis-specific poly(A) polymerase (TPAP) is a cytoplasmic poly(A) polymerase that is highly expressed in round spermatids. We identified germ cell-specific gene 1 (GSG1) as a TPAP interaction partner protein using yeast two-hybrid and coimmunoprecipitation assays. Subcellular fractionation analysis showed that GSG1 is exclusively localized in the endoplasmic reticulum (ER) of mouse testis where TPAP is also present. In NIH3T3 cells cotransfected with TPAP and GSG1, both proteins colocalize in the ER. Moreover, expression of GSG1 stimulates TPAP targeting to the ER, suggesting that interactions between the two proteins lead to the redistribution of TPAP from the cytosol to the ER. Structured summary:MINT-6168263: Gsg1 (Q8R1W2), TPAP (Q9WVP6) and Calmegin (P52194) colocalize (0403) by cosedimentation (0027) MINT-6168204, MINT-6168178: Gsg1 (Q8R1W2) and TPAP (Q9WVP6) colocalize (0403) by fluorescence microscopy (0416) MINT-6167930: Gsg1 (Q8R1W2) physically interacts (0218) with TPAP (Q9WVP6) by two-hybrid (0018) MINT-6168112, MINT-6168011, MINT-6168054: Gsg1 (Q8R1W2) physically interacts (0218) with TPAP (Q9WVP6) by coimmunoprecipitation (0019) MINT-61668069, MINT-6168101: Gsg1 (Q8R1W2)physically interacts (0218) with TPAP (Q9WVP6) by pull-down (0096) MINT-6168218: Gsg1 (Q8R1W2) and GRP78 (P20029) colocalize (0403) by fluorescence microscopy (0416) MINT-6168381: TPAP (Q9WVP6) and GRP78 (P20029) colocalize (0403) by fluorescence microscopy (0416)

Poly(A) polymerase (PAP), which adds poly(A) tails to the 3′ end of mRNA, can be phosphorylated at several sites in the C-terminal domain. Phosphorylation often mediates regulation by extracellular stimuli, suggesting PAP may be regulated by such stimuli. In this study, we found that phosphorylation of PAP was increased upon growth stimulation and that the mitogen-activated protein kinase ERK was responsible for the increase in phosphorylation. We identified serine 537 of PAP as a unique phosphorylation site by ERK. PAP phosphorylation of serine 537 by ERK increased its nonspecific polyadenylation activity in vitro. This PAP activity was also activated by stimulation of ERK with phorbol-12-myristate-13-acetate in vivo. These data suggest that ERK is a novel regulatory kinase for PAP and further, that PAP activity could be regulated by extracellular stimuli through an ERK-dependent signaling pathway(s).

Poly(A) polymerase (PAP) play an essential role for maturation of mRNA by adding the adenylate residues at the 3' end. PAP functions are regulated through protein-protein interaction at its C-terminal region. In this study, cyclophilin A (CypA), a member of the peptidyl-prolyl cis-trans isomerase family, was identified as a partner protein interacting with the C-terminal region PAP. The interaction between PAP and CypA was inhibited by the immunosuppressive drug cyclosporine A. Deletion analysis revealed that the N-terminal 56 residues of CypA are sufficient for the interaction with PAP. Interestingly, we observed that PAP and CypA colocalize in the nucleus during SDF-1-induced chemotaxis, implying that CypA could be involved in the regulation of polyadenylation by PAP in the chemotactic cells.

No abstract

No abstract