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(Lead section needs to include a summary of her lab's research)

Prof. Johnson’s lab studies the mechanisms of co-transcriptional pre-mRNA splicing in Saccharomyces cerevisiae.

Research
Johnson's research focuses on understanding gene regulation, chromatin modification, RNA splicing and how regulating splicing allows cells to respond to their environment. Specifically, her group studies the spliceosome, a macromolecular "machine" made of five subunits that interacts with a pre-messenger RNA to produce an edited version, leading to appropriate translation into proteins. Her group has provided evidence that spliceosome assembly around a nascent mRNA transcript is regulated by histone modifications in the chromatin of the transcribed region.

Eukaryotic genes are interrupted by stretches of noncoding sequence (introns), which are removed from the newly-synthesized RNA by the spliceosome, a dynamic ribonucleoprotein complex made up of 5 highly structured snRNAs and over a hundred snRNA-associated proteins. Although RNA synthesis and RNA splicing have been analyzed as biochemically separate reactions, recent studies demonstrate that these processes are spatially and temporally coordinated. ''Maniatis T, Reed R (2002) An extensive network of coupling among gene expression machines. Nature 416: 499–506. Transcription of DNA is strongly influenced by its packaging. histones undergo extensive post-translational modifications on their N-terminal tails including acetylation, ubiquitination, methylation, and phosphor- ylation, which alter the chromatin and, in turn, affect transcription. [modify this]''

During her postdoctoral training in the lab of Dr. John Abelson, Prof. Johnson's research challenged pre-existing views on how the spliceosome assembles, providing evidence that there was flexibility in the order in which snRNAs associated with the 5' splice site.

Research from the Johnson lab has contributed to our understanding of how epigenetic modifications regulate pre-mRNA splicing. They discovered that the histone acetyltransferase (HAT) activity of Gcn5, a component of the the transcriptional coactivator complex SAGA, is required for the recruitment of U2 snRNPs Msl1 and Lea1 to the branchpoint and subsequent spliceosome assembly.

Mentorship and leadership in Education
In addition to her passion for research Prof. Johnson is a committed mentor and educator, for which she has been recognized with numerous awards. In 2013 she received the UCSD Chancellor’s Associates Award for Excellence in Undergraduate Teaching, and she was selected as one of the Top 20 Women Professors in California. In particular, Prof. Johnson is devoted to promote diversity, equity and inclusion in STEM, and as such she was awarded the UCLA Academic Senate Award for Career Commitment to Diversity, Equity and Inclusion and the UCLA Life Sciences Award for Inclusive Excellence through teaching, mentorship, service and research.

Prof. Johnson has also focused on developing programs to create transformative learning experiences for undergraduates including the UCLA-HHMI Pathways to Success Program, which seeks to support the success of students from diverse backgrounds in STEM. The program is a comprehensive strategy to provide students with an authentic research experience early in their academic careers. The program has three key components:  (1) A research-based laboratory course, (2) a mentoring network that integrates peer and hierarchical mentoring, and (3) intensive learning communities. As of 2021, the program has enrolled more than 125 students, and many of them have gone on to doctoral programs, medical school, MD/PhD programs, and a host of other STEM-related careers.