{'fraction_non_alphanumeric': 0.018535681186283594, 'fraction_numerical': 0.009267840593141797, 'mean_word_length': 5.242774566473988, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Isolation of thermolabile mutant RNA polymerase II from fission yeast Schizosaccharomyces pombe with mutations in the subunit 3 gene.

Subunit alpha of prokaryotic RNA polymerases plays key roles in protein-protein contacts for both subunit assembly and transcription activation. To gain an insight into the roles of subunit 3, the eukaryotic homologue of alpha, temperature-sensitive mutants of the fission yeast, Schizosaccharomyces pombe, have been isolated after transformation of the mutagenized rpb3 gene encoding mutant subunit 3 of RNA polymerase II. A total of 68 ts mutants were classified into two groups: mutants comprising one group ceased growing immediately after a temperature up-shift, while mutants comprising the other group exhibited delayed growth arrest at high temperatures. RNA polymerase II partially purified from Ts54, one of the group 2 mutants, was thermolabile in vitro, as measured by a non-specific transcription assay. This mutant carries double mutations in domain A of subunit 3, and thus can be used as a reference mutant of RNA polymerase II.