Subtractive PCR?

[Robert Brown]

In article <1991Dec18.213347.27747 at magnus.acs.ohio-state.edu> cbeall at magnus.acs.ohio-state.edu (Clifford J Beall) writes:
>Dear Methods people,
>
>Does anyone have a method for subtracting cDNA prior to PCR?
>We are using degenerate primers and want to clone a cell specific
>message.  It seems one could hybridize with [+] cDNA with [-] RNA,
>remove hybrids, then treat the remainder with RNAse.  Is HAP still the
>method of choice for hybrid removal and does anyone know conditions
>for this?  Thanks in advance.
>				Cliff Beall
>				Ohio State Biotech. Ctr.

Invitrogen sells a kit for subtractive hybridization using biotinylation of
the [-] RNA and extraction of the hybrid into phenol after binding
streptavidin. 
good luck