Simplicity amidst complexity in transcriptional initiation

Refactoring transcription factors for metabolic engineering

Due to the ability to regulate target metabolic pathways globally and dynamically, metabolic regulation systems composed of transcription factors have been widely used in metabolic engineering and synthetic biology. This review introduced the categories, action principles, prediction strategies, and related databases of transcription factors. Then, the application of global transcription machinery engineering technology and the transcription factor-based biosensors and quorum sensing systems are overviewed. In addition, strategies for optimizing the transcriptional regulatory tools' performance by refactoring transcription factors are summarized. Finally, the current limitations and prospects of constructing various regulatory tools based on transcription factors are discussed. This review will provide theoretical guidance for the rational design and construction of transcription factor-based metabolic regulation systems.

Nucleotide excision repair syndromes: molecular basis and clinical symptoms

The phenotypic consequences of a nucleotide excision repair (NER) defect in man are apparent from three distinct inborn diseases characterized by hypersensitivity of the skin to ultraviolet light and a remarkable clinical and genetic heterogeneity. These are the prototype repair syndrome, xeroderma pigmentosum (XP) (seven genetic complementation groups, designated XP-A to XP-G), Cockayne's syndrome (two groups: CS-A and CS-B) and PIBIDS, a peculiar photosensitive form of the brittle hair disease trichothiodystrophy (TTD, at least two groups of which one equivalent to XP-D). To investigate the mechanism of NER and to resolve the molecular defect in these NER deficiency diseases we have focused on the cloning and characterization of human DNA repair genes. One of the genes that we cloned is ERCC3. It specifies a chromatin binding helicase. Transfection and microinjection experiments demonstrated that mutations in ERCC3 are responsible for XP complementation group B, a very rare form of XP that is simultaneously associated with Cockayne's syndrome (CS). The ERCC3 protein was found to be part of a multiprotein complex (TFIIH) required for transcription initiation of most structural genes and for NER. This defines the additional, hitherto unknown vital function of the gene. This ERCC3 gene and several other NER genes involved in transcription initiation will be discussed.