Multivariate statistical analysis of electron micrographs of a mammalian transcription initiation complex

We describe the appearance of the murine ribosomal protein (rp) L32 gene transcription initiation complex as determined by electron image analysis. Using a fractionated nuclear extract enriched for transcription factors necessary for rpL32 gene transcription in vitro and a DNA fragment containing the rpL32 gene promoter, the transcription initiation complex was prepared and viewed by standard transmission electron microscopy. Image analysis demonstrated that the complex was a multilobed structure.