A/T stretches

Keith Elliston elliston at av8tr.UUCP
Fri Feb 15 13:09:38 EST 1991

In article <60*.S=suter2.OU=urz.O=unibas.PRMD=SWITCH.ADMD=ARCOM.C=CH. at MHS>, suter2 at urz.unibas.ch (clemens suter-crazzolara) writes:
> dear colleagues,
> we have cloned a rna gene of 1100 bp. this gene contains 4 stretches of at least
>  10 A or 10 T residues, one of them located between enhancer and promoter.
> does anyone know whether these A or T rich stretches have a function,
> or how they have arisen ? can they influence transcription ?
> The gene is probably transcribed by PolII and it is mammalian.

Check out Biochemistry 29:6161-6171 (1990) by Chan et al.  the paper is
titled "Physical Studies of DNA premelting equilibria in duplexes with
and without homo dA:dT Tracts:  Correlations with DNA bending."

The authors talk about a "premelting" that occurs in stretches of DNA
that are poly dA, poly dT.  This premelting occurs at 37 C. and may be
involved in the disruption of "bent" DNA.  The authors also speculate
that these poly dA poly dT stretches may be involved in ligand binding
at these poly dA poly dT sites.

Other refs to look at may be:

Breslauer et al. (1987) Proc. Natl. Acad. Sci. USA 84:8922-8926.

Herrera and Chaires (1989) Biochemistry 28:1993-2000.

Good luck...

Keith Elliston

Keith O. Elliston          elliston at av8tr.UUCP           elliston at msdrl.com
AA5A N9734U                elliston at mbcl.rutgers.edu     elliston at biovax.bitnet

"Fly because you have to, to keep some semblance of sanity."

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