HILDA HIU YIN YU

Home Department
Microbiology and Molecular Genetics, College of Medicine

Thesis Advisor
Ming Tan - Microbiology and Molecular Genetics, College of Medicine

Co-thesis Advisor
Dennis Kibler - Information and Computer Science

Co-thesis Advisor
G. Wesley Hatfield – Microbiology and Molecular Genetics, College of Medicine

Email


The Tan lab studies the regulation of gene expression in Chlamydia, focusing in on the mechanisms of transcriptional regulation. In bacteria, transcription is initiated by the binding of RNA polymerase to conserved DNA elements, know as the promoter, that are located upstream of the coding region for a gene. RNA polymerase consists of a core enzyme, which provides the enzymatic activity, and a sigma factor, that recognizes a specific promoter. This activity can be regulated by transcription factors, such as activators and repressors that increase and decrease transcription respectively, and by alternative sigma factors which, coupled to the same core enzyme, can allow the RNA polymerase to recognize different promoters.

The Chlamydia Genome Project has predicted 3 sigma factors: a major sigma factor that is responsible for transcribing most of the genes required for everyday survival, and 2 alternative sigma factors that transcribe special classes of genes in other bacteria. Hilda Yu’s primary project involves the study of an alternative sigma factor, σ28 . She has developed an in vitro transcription assay to investigate regulation by this alternative sigma factor. Using this system she has been able to demonstrate that transcription of one chlamydial gene, hctB, is regulated by s28. To uncover other genes that might be regulated by σ28, she has devised several bioinformatics methods. In collaboration with Dr. Dennis Kibler, she is developing a weighted computer algorithm, based on conserved σ28-like promoters. Furthermore she is using DNA microarrays to identify σ28-regulated genes either based on transcription by σ28 RNA polymerase or by clustering of genes with similar transcriptional profiles to the hctB gene. σ28-regulation of the candidate promoters of these genes will be confirmed using an in vitro transcription system.

Publications

Yu, H.H.Y. and Tan, M. σ28 RNA polymerase regulates hctB, a late developmental gene in Chlamydia. Molecular Microbiology (Submitted).