B-gal transcription

[Jillian Johnston]

I am trying to make capped B-gal mRNA (3kb) for translation
in Xenopus embryos using an SP6 polymerase.  I can't get full
length transcripts.  I have tried upping the amount of rNTPs but
this didn't help.  Before I waste anymore reagents (esp. cap
analog) I'd like some advice on possible areas that I should try.
I have no trouble making transcripts up to 2kb.
Thanks in advance for your help.
Jill Johnston