Northern

[xia at WARREN.MED.HARVARD.EDU]

          Hi, happy Friday, my netter friend!
          I'm recently doing Northern blot analysis on RNA samples
          isolated from cells transfected with my plasmid constructs
          containing human growth hormon gene (isolated 2 day after
          transfection). I probed the blot with BamHI-BglII hGH gene
          fragment(about 1.8 kb) labeled with 32P. The things bother
          me are as follow:  I always get long smear bands and even
          the cells transfected with promoter-less constructs. Is it
          possible that the plasmid containing hGH gene sequence(I
          have used 30 ug per transfection then used TriReagent
          isolated total RNA which finally dissolved in 60 ul DEPC
          H2O) contaminated my RNA samples, and these plasmid DNA have
          been partially degraded?

          Any explanations and suggestions? Thanx