Path: utzoo!utgpu!watserv1!watmath!att!emory!wuarchive!uunet!av8tr!elliston
From: elliston@av8tr.UUCP (Keith Elliston)
Newsgroups: bionet.general
Subject: Re: A/T stretches
Message-ID: <626@av8tr.UUCP>
Date: 15 Feb 91 18:09:38 GMT
References: <60*.S=suter2.OU=urz.O=unibas.PRMD=SWITCH.ADMD=ARCOM.C=CH.@MHS>
Organization: Aviators Online BBS, Somerville, NJ
Lines: 37

In article <60*.S=suter2.OU=urz.O=unibas.PRMD=SWITCH.ADMD=ARCOM.C=CH.@MHS>, suter2@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@av8tr.UUCP           elliston@msdrl.com
AA5A N9734U                elliston@mbcl.rutgers.edu     elliston@biovax.bitnet

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