TY  - JOUR
A1  - Ud-Din, Aziz
A1  - Rauf, Mamoona
A1  - Ghafoor, S.
A1  - Khattak, M. N. K.
A1  - Hameed, M. W.
A1  - Shah, H.
A1  - Jan, S.
A1  - Muhammad, K.
A1  - Rehman, A.
A1  - Inamullah, 
T1  - Efficient use of artificial micro-RNA to downregulate the expression of genes at the post-transcriptional level in Arabidopsis thaliana
JF  - Genetics and molecular research
N2  - Micro-RNAs are cellular components regulating gene expression at the post-transcription level. In the present study, artificial micro-RNAs were used to decrease the transcript level of two genes, AtExpA8 (encoding an expansin) and AHL25 (encoding an AT-hook motif nuclear localized protein) in Arabidopsis thaliana. The backbone of the Arabidopsis endogenous MIR319a micro-RNA was used in a site-directed mutagenesis approach for the generation of artificial micro-RNAs targeting two genes. The recombinant cassettes were expressed under the control of the CaMV 35S promoter in individual A. thaliana plants. Transgenic lines of the third generation were tested by isolating total RNA and by subsequent cDNA synthesis using oligo-dT18 primers and mRNAs as templates. The expression of the two target genes was checked through quantitative realtime polymerase chain reaction to confirm reduced transcript levels for AtExpA8 and AHL25. Downregulation of AtExpA8 resulted in the formation of short hypocotyls compared with those of the wild-type control in response to low pH and high salt concentration. This technology could be used to prevent the expression of exogenous and invading genes posing a threat to the normal cellular physiology of the host plant.
KW  - Artificial micro-RNA
KW  - Arabidopsis thaliana
KW  - qRT-PCR
KW  - AtExpA8
KW  - AHL25
Y1  - 2016
U6  - https://doi.org/10.4238/gmr.15027439
SN  - 1676-5680
VL  - 15
PB  - FUNPEC
CY  - Ribeirao Preto
ER  - 
TY  - JOUR
A1  - Czesnick, Hjördis
A1  - Lenhard, Michael
T1  - Antagonistic control of flowering time by functionally specialized poly(A) polymerases in Arabidopsis thaliana
JF  - The plant journal
N2  - Polyadenylation is a critical 3-end processing step during maturation of pre-mRNAs, and the length of the poly(A) tail affects mRNA stability, nuclear export and translation efficiency. The Arabidopsis thaliana genome encodes three canonical nuclear poly(A) polymerase (PAPS) isoforms fulfilling specialized functions, as reflected by their different mutant phenotypes. While PAPS1 affects several processes, such as the immune response, organ growth and male gametophyte development, the roles of PAPS2 and PAPS4 are largely unknown. Here we demonstrate that PAPS2 and PAPS4 promote flowering in a partially redundant manner. The enzymes act antagonistically to PAPS1, which delays the transition to flowering. The opposite flowering-time phenotypes in paps1 and paps2 paps4 mutants are at least partly due to decreased or increased FLC activity, respectively. In contrast to paps2 paps4 mutants, plants with increased PAPS4 activity flower earlier than the wild-type, concomitant with reduced FLC expression. Double mutant analyses suggest that PAPS2 and PAPS4 act independently of the autonomous pathway components FCA, FY and CstF64. The direct polyadenylation targets of the three PAPS isoforms that mediate their effects on flowering time do not include FLC sense mRNA and remain to be identified. Thus, our results uncover a role for canonical PAPS isoforms in flowering-time control, raising the possibility that modulating the balance of the isoform activities could be used to fine tune the transition to flowering. Significance Statement The length of the poly(A) tail affects mRNA stability, nuclear export and translation efficiency. Arabidopsis has three isoforms of nuclear poly(A) polymerase (PAPS): PAPS1 plays a major role in organ growth and plant defence. Here we show that PAPS2 and PAPS4 redundantly promote flowering and act antagonistically to PAPS1, which delays flowering. We suggest that modulating the activity of these isoforms fine-tunes the transition to flowering.
KW  - polyadenylation
KW  - 3-end processing
KW  - poly(A) polymerase
KW  - flowering time
KW  - autonomous pathway
KW  - Arabidopsis thaliana
Y1  - 2016
U6  - https://doi.org/10.1111/tpj.13280
SN  - 0960-7412
SN  - 1365-313X
VL  - 88
SP  - 570
EP  - 583
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -