담배 callus를 $5{ imes}10^{-7};M$ kinetin/$10^{-8};M$ IAA 배지 또는 $10^{-5};M$ kinetin/$10^{-5};M$ IAA 배지에서 15~20일 배양했을 때 shoot이 형성되었다. 두 조건에서 형성된 shoot에 있어서 peroxidase의 활성도는 shoot을 형성하지 않은 callus 보다 낮았다. 또한 $10^{-8};M$ kinetin 배지에서 형성된 shoot에서는 cathodic isoperoxidases의 양이 증가한 반면 $10^{-5}M$ Kinetin 배지에서 형성된 shoot에서는 anodic isoperoxidases가 증가하였다. 담배 callus의 mRNA를 분리하여 in vitro translation을 행한 결과 최소한 5개의 isoperoxidases mRNA가 존재함을 확인하였으며, $poly(A)^-RNA$에서도 peroxidase가 합성되었다. 정상배지에서 4주 배양한 callus에서는 $poly(A)^+$ RNA와 $poly(A)^-$ $RNA{mu}g$ 당 거의 같은 양의 peroxidase가 합성되었으나, $10^{-5}M;M$ kinetin 배지에서 형성된 shoot에서는 $poly(A)^+$ RNA에서보다 $poly(A)^-$ RNA에서 더많은 peroxidase가 합성되었다. 또한 $poly(A)^-$ RNA에서는 $poly(A)^+$ RNA보다 cathodic isoperoxidases가 더 적게 translation되는 사실도 확인하였다.
Tobacco callus grown on $5{ imes}10^{-7};M$ kinetin/$10^{-8};M$ IAA or $10^{-5};M$ kinetin/$10^{-5}$ IAA formed shoots after 15-20 days of culture. The total peroxidase activities in shoots were lower than those of non-shoot-forming callus. However, cathodic isoperoxidases were increased significantly in shoots formed on $10^{-8};M$ IAA media while anodic isoperoxidases were increased in shoots formed on $10^{-5};M$ kinetin media as is the case of shoot initiating callus. The gene expression patterns of isoperoxidases in shoot and non-shoot-forming tissue were also examined by rabbit reticulocyte lysate in vitro translation system. These studies indicate that fraction of translatable $poly(A)^-$ isoperoxidase mRNA was increased considerably in shoots formed on $10^{-5};M$ kinetin, whereas $poly(A)^+$ isoperoxidase mRNA contents were twice higher than $poly(A)^-$ isoperoxidase mRNAs in non-shoot-forming callus. At the present time, at least five isoperoxidases could be detected from the translation mixture of total cellular RNA. Preliminary translation data indicate that less cathodic isoperoxidases and more anodic isoperoxidases were expressed from $poly(A)^-$ RNAs than from $poly(A)^+$ RNAs.
