As the major task of sequencing the human genome is near completion and full complement of human genes are catalogued, attention will be focused on the ultimate goal: to understand the normal biological functions of these genes, and how alterations lead to disease states. In this task there is a severe limitation in working with human material, but the mouse has been adopted as the favored animal model because of the available genetic resources and the highly conserved gene conservation linkage organization. In just of ten years since the first gene-targeting experiments were p- formed in embryonic stem (ES) cells and mutations transmitted through the mouse germline, more than a thousand mouse strains have been created. These achievements have been made possible by pioneering work that showed that ES cells derived from preimplantation mouse embryos could be cultured for prolonged periods without differentiation in culture, and that homologous rec- bination between targeting constructs and endogenous DNA occurred at a f- quency sufficient for recombinants to be isolated. In the next few years the mouse genome will be systematically altered, and the techniques for achi- ing manipulations are constantly being streamlined and improved.

The effort to sequence the human genome is now moving toward a c- clusion. As all of the protein coding sequences are described, an increasing emphasis will be placed on understanding gene function and regulation. One important aspect of this analysis is the study of how transcription factors re- late transcriptional initiation by RNA polymerase II, which is responsible for transcribing nuclear genes encoding messenger RNAs. The initiation of Class II transcription is dependent upon transcription factors binding to DNA e- ments that include the core or basal promoter elements, proximal promoter elements, and distal enhancer elements. General initiation factors are involved in positioning RNA polymerase II on the core promoter, but the complex - teraction of these proteins and transcriptional activators binding to DNA e- ments outside the core promoter regulate the rate of transcriptional initiation. This initiation process appears to be a crucial step in the modulation of mRNA levels in response to developmental and environmental signals. Transcription Factor Protocols provides step-by-step procedures for key techniques that have been developed to study DNA sequences and the protein factors that regulate the transcription of protein encoding genes. This volume is aimed at providing researchers in the field with the well-detailed protocols that have been the hallmark of previous volumes of the Methods in Molecular (TM) Biology series.

The effort to sequence the human genome is now moving toward a c- clusion. As all of the protein coding sequences are described, an increasing emphasis will be placed on understanding gene function and regulation. One important aspect of this analysis is the study of how transcription factors re- late transcriptional initiation by RNA polymerase II, which is responsible for transcribing nuclear genes encoding messenger RNAs. The initiation of Class II transcription is dependent upon transcription factors binding to DNA e- ments that include the core or basal promoter elements, proximal promoter elements, and distal enhancer elements. General initiation factors are involved in positioning RNA polymerase II on the core promoter, but the complex - teraction of these proteins and transcriptional activators binding to DNA e- ments outside the core promoter regulate the rate of transcriptional initiation. This initiation process appears to be a crucial step in the modulation of mRNA levels in response to developmental and environmental signals. Transcription Factor Protocols provides step-by-step procedures for key techniques that have been developed to study DNA sequences and the protein factors that regulate the transcription of protein encoding genes. This volume is aimed at providing researchers in the field with the well-detailed protocols that have been the hallmark of previous volumes of the Methods in Molecular (TM) Biology series.

As the major task of sequencing the human genome is near completion and full complement of human genes are catalogued, attention will be focused on the ultimate goal: to understand the normal biological functions of these genes, and how alterations lead to disease states. In this task there is a severe limitation in working with human material, but the mouse has been adopted as the favored animal model because of the available genetic resources and the highly conserved gene conservation linkage organization. In just of ten years since the first gene-targeting experiments were p- formed in embryonic stem (ES) cells and mutations transmitted through the mouse germline, more than a thousand mouse strains have been created. These achievements have been made possible by pioneering work that showed that ES cells derived from preimplantation mouse embryos could be cultured for prolonged periods without differentiation in culture, and that homologous rec- bination between targeting constructs and endogenous DNA occurred at a f- quency sufficient for recombinants to be isolated. In the next few years the mouse genome will be systematically altered, and the techniques for achi- ing manipulations are constantly being streamlined and improved.