Cytoplasmic polyadenylation regulates mRNA stability and translation and is required for early development and synaptic plasticity. The GLD-2 poly(A) polymerase catalyzes cytoplasmic polyadenylation in the germline of metazoa. Among vertebrates, the enzyme is encoded by two isoforms of mRNA that differ only in the length of their 3'-UTRs. Here we focus on regulation of vertebrate GLD-2 mRNA. We...

OBJECTIVE Statins have been shown to increase endothelial nitric oxide synthase expression via enhanced mRNA stability. Because the poly(A) tail is an important determinant of transcript stability, we sought to characterize the effect of statins on eNOS mRNA 3' polyadenylation. METHODS AND RESULTS Endothelial cells treated with statins had a time- and dose-dependent increase in eNOS transcrip...

Termination codons in mRNA molecules are typically specified directly by the sequence of the corresponding gene. However, in mitochondria of a few eukaryotic groups, some mRNAs contain the termination codon UAA deriving one or both adenosines from transcript polyadenylation. Here, we show that a similar phenomenon occurs for a substantial number of nuclear genes in Blastocystis spp., divergent ...

The pre-mRNA processing strategy of the B19 virus is unique among parvoviruses. B19 virus-generated pre-mRNAs are transcribed from a single promoter and are extensively processed by alternative splicing and alternative polyadenylation to generate 12 transcripts. Blockage of the production of full-length B19 virus transcripts at the internal polyadenylation site [(pA)p] was previously reported t...

In most eukaryotic cells, the poly(A) tail at the 3'-end of messenger RNA (mRNA) is essential for nuclear export, translatability, stability and transcription termination. Poly(A) tail formation involves multi-protein complexes that interact with specific sequences in 3'-untranslated region (3'-UTR) of precursor mRNA (pre-mRNA). Here we have performed a computational analysis of a large EST and...

We have previously identified a G-rich sequence (GRS) as an auxiliary downstream element (AUX DSE) which influences the processing efficiency of the SV40 late polyadenylation signal. We have now determined that sequences downstream of the core U-rich element (URE) form a fundamental part of mammalian polyadenylation signals. These novel AUX DSEs all influenced the efficiency of 3'-end processin...

mRNA-specific polyadenylation can be assayed in vitro by using synthetic RNAs that end at or near the natural cleavage site. This reaction requires the highly conserved sequence AAUAAA. At least two distinct nuclear components, an AAUAAA specificity factor and poly(A) polymerase, are required to catalyze the reaction. In this study, we identified structural features of the RNA substrate that ar...

Nanos protein promotes abdominal structures in Drosophila embryos by repressing the translation of maternal hunchback mRNA in the posterior. To study the mechanism of nanos-mediated translational repression, we first examined the mechanism by which maternal hunchback mRNA is translationally activated. In the absence of nanos activity, the poly(A) tail of hunchback mRNA is elongated concomitant ...

To elucidate the mechanism by which poly(A) polymerase functions in the 3'-end processing of pre-mRNAs, polyadenylation-specific RNP complexes were isolated by sedimentation in sucrose density gradients and the fractions were analyzed for the presence of the enzyme. At early stages of the reaction, the RNP complexes were resolved into distinct peaks which sedimented at approximately 18S and 25S...

The Arabidopsis thaliana ortholog of the 30-kD subunit of the mammalian Cleavage and Polyadenylation Specificity Factor (CPSF30) has been implicated in the responses of plants to oxidative stress, suggesting a role for alternative polyadenylation. To better understand this, poly(A) site choice was studied in a mutant (oxt6) deficient in CPSF30 expression using a genome-scale approach. The resul...