Transcriptomic analyses to estimated poly(A)-tail lengths in paps1-1 mutant pollen tubes
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ABSTRACT: Polyadenylation of mRNAs is critical for their export from the nucleus, stability and efficient translation. The Arabidopsis thaliana genome encodes three isoforms of canonical nuclear poly(A) polymerase (PAPS) that redundantly polyadenylate the bulk of pre-mRNAs. However, their distinct mutant phenotypes and transcriptome studies have indicated that subsets of pre-mRNAs are preferentially polyadenylated by either PAPS1 or the two very similar PAPS2 and PAPS4 proteins. Such functional specialization raises the possibility of modulating the balance of activities between the isoforms to alter poly(A) lengths of sets of transcripts, providing an additional level of gene-expression control in plants. Here we test this notion by studying the function of PAPS1 in pollen-tube growth and guidance. Pollen tubes growing through female tissue acquire the competence to find ovules efficiently and upregulate PAPS1 expression more strongly than in vitro grown pollen tubes. Using the temperature-sensitive paps1-1 allele we show that PAPS1 activity during pollen-tube growth is required for full acquisition of competence, resulting in inefficient fertilization by paps1-1 mutant pollen tubes. While these mutant pollen tubes germinate and grow at the same rates as wild-type pollen tubes, they are compromised in locating the micropyles of ovules. Transcriptomic analyses indicate that previously identified competence-associated genes are less expressed in paps1-1 mutant than in wild-type pollen tubes. Estimating the poly(A)-tail lengths of transcripts in mutant and wild-type pollen tubes suggests that polyadenylation by PAPS1 is associated with reduced transcript abundance. Our results therefore suggest that PAPS1 upregulation during pollen-tube growth through the style plays a key role in the acquisition of competence and support the notion that plants can modulate the balance of activity between PAPS isoforms to regulate gene expression.
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE207509 | GEO | 2023/02/21
REPOSITORIES: GEO
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