Monoclonal antibodies that recognize transcription unit proteins on newt lampbrush chromosomes

Abstract

We prepared hybridoma cells lines from mice injected with newt germinal vesicle proteins. We tested culture supernates from these cell lines for antibodies that bound to specific morphological structures in lampbrush chromosome preparation (nucleoli, loops, chromomeres, etc.). Four mAbs that recognize antigens on the lateral transcription loops are described here. We suggest that these antigens are proteins associated with nascent RNA transcripts, although they are not among the 30-40 kD 'core' heterogeneous nuclear ribonucleoproteins.