Fidelity of polyadenylation in plants

Arthur Hunt AGHUNT00 at
Thu Sep 15 20:32:19 EST 1994

In article <354nir$rsp at>
"Peter Hare" <HARE at> writes:
>Could anyone refer me to any reports of variable sites of
>addition of a poly(A) tail from a single polyadenylation signal?
>I have recently sequenced the 3' end of an Arabidopsis cDNA, the
>sequence of which has already been published. The cDNA I have
>sequenced has been truncated 7 bp before the sequence published.
>In both cases the same polyadenylation signal appears to have
>been used. The rest of the 3' untranslated region is identical in
>both cDNAs. The two poly(A) tails differ in length by only a
>single A.
>Is this a common occurrence in transcription of plant genes? None
>of the reviews of mRNA 3' formation I have seen mention such a
>phenomenon. I would also greatly appreciate any input regarding
>how this apparently anomalous situation may have arisen.
>Peter Hare
>Dept. of Botany
>University of Natal
>South Africa
>hare at
What you have described (multiple polyadenylation sites in a plant
transcription unit) is quite the norm in plant genes.  There may be more, but
I am aware of only two cases where a single poly(A) site is used.
The situation you describe (two sites 7 nts apart) might be due to different
poly(A) signals, but is more likely due to the use of different cleavage/
polyadenylation sites.
   It is easy to think of this as anomolous if one thinks like a mammal, but
this situation is really the norm in all other organisms (it has been reported
in yeast, and is not unlike how rho-dependent termination sites look in E.
E. coli).
Arthur G. Hunt
Department of Agronomy
University of Kentucky
Lexington, KY 40546-0091 USA
Tel:  (606) 257-3637
Fax:  (606) 323-1952
email:  aghunt00 at

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