The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

/pdf/initial-sequencing-and-analysis-of-the-human-genome-5dapk1rsx1.pdf

Initial sequencing and analysis of the human genome.

https://njc.rockefeller.edu/pdf4/Class2-LeeAmbros1993.pdf

The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14

We have designed a system for targeted gene expression that allows the selective activation of any cloned gene in a wide variety of tissue- and cell-specific patterns. The gene encoding the yeast transcriptional activator GAL4 is inserted randomly into the Drosophila genome to drive GAL4 expression from one of a diverse array of genomic enhancers. It is then possible to introduce a gene containing GAL4 binding sites within its promoter, to activate it in those cells where GAL4 is expressed, and to observe the effect of this directed misexpression on development. We have used GAL4-directed transcription to expand the domain of embryonic expression of the homeobox protein even-skipped. We show that even-skipped represses wingless and transforms cells that would normally secrete naked cuticle into denticle secreting cells. The GAL4 system can thus be used to study regulatory interactions during embryonic development. In adults, targeted expression can be used to generate dominant phenotypes for use in genetic screens. We have directed expression of an activated form of the Dras2 protein, resulting in dominant eye and wing defects that can be used in screens to identify other members of the Dras2 signal transduction pathway.

Targeted gene expression as a means of altering cell fates and generating dominant phenotypes.

A simple and efficient method for synthesizing pure single stranded RNAs of virtually any structure is described. This in vitro transcription system is based on the unusually specific RNA synthesis by bacteriophage SP6 RNA polymerase which initiates transcription exclusively at an SP6 promoter. We have constructed convenient cloning vectors that contain an SP6 promoter immediately upstream from a polylinker sequence. Using these SP6 vectors, optimal conditions have been established for in vitro RNA synthesis. The advantages and uses of SP6 derived RNAs as probes for nucleic acid blot and solution hybridizations are demonstrated. We show that single stranded RNA probes of a high specific activity are easy to prepare and can significantly increase the sensitivity of nucleic acid hybridization methods. Furthermore, the SP6 transcription system can be used to prepare RNA substrates for studies on RNA processing (1,5,9) and translation (see accompanying paper).

Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter

The 2016 revision of the World Health Organization classification of lymphoid neoplasms

Purpose of reviewThis review summarizes the recent progress in defining the patterns of genetic evolution giving rise to relapse in follicular lymphoma and multiple myeloma, and discusses their implications with respect to ‘personalized medicine’.Recent findingsHigh-throughput sequencing studies hav

Common progenitor cells in mature B-cell malignancies: implications for therapy.

High levels of BACH2 associated with lower levels of BCL2 transcript abundance in t(14;18)(q21;q34) translocation positive non-Hodgkin's lymphoma

Purpose of review This review summarizes the recent progress in defining the patterns of genetic evolution giving rise to relapse in follicular lymphoma and multiple myeloma, and discusses their implications with respect to ‘personalized medicine’. Recent findings High-throughput sequencing studies have uncovered a large degree of clonal heterogeneity within tumors, and found that subclones have a variable contribution to relapse. Recent studies aimed at defining patterns of clonal evolution have revealed that serial tumors in some malignancies share their ancestry in a less evolved common progenitor cell (CPC) that bears only a subset of the mutations that are present in the fully evolved tumors that present clinically. This pattern of ‘divergent evolution’ means that the majority of ‘actionable mutations’ in tumor specimens are absent within the progenitors that give rise to relapse. Summary Follicular lymphoma and multiple myeloma are clinically, biologically and genetically distinct mature B-cell malignancies. However, recent studies have found them to share important similarities in their patterns of genetic evolution. Tumor cells that constitute subclonal populations within these tumors, or between consecutive tumors, share their origins within a genetically less evolved common progenitor cell. This pattern of evolution indicates that current therapies are unable to eradicate these less evolved populations that are at the root of relapse. This suggests that in order to obtain the best results with modern ‘targeted therapies’ that are directed towards ‘actionable mutations’, these mutations should be considered within the context of the evolutionary stage at which mutations are acquired, not simply on a presence or absence basis.

C URRENT OPINION Common progenitor cells in mature B-cell malignancies: implications for therapy

Preparing electrocompetent bacteria is considerably easier than preparing cells for transformation by chemical methods. Bacteria are simply grown to mid-log phase, chilled, centrifuged, washed extensively with ice-cold buffer or H2O to reduce the ionic strength of the cell suspension, and then suspended in an ice-cold buffer containing 10% glycerol. DNA may be introduced immediately into the bacteria by exposing them to a short high-voltage electrical discharge. Alternatively, the cell suspension may be snap-frozen and stored at -70°C for up to 6 mo before electroporation, without loss of transforming efficiency.

Transformation of Escherichia coli by Electroporation

The purpose of hot start polymerase chain reaction (PCR) is to optimize the yield of the desired amplified product in PCRs and, simultaneously, to suppress nonspecific amplification and formation of primer dimers. This is achieved by withholding an essential component of the PCR-the DNA polymerase, or the primers, for example-until the reaction mixture has been heated to a temperature that inhibits hybridization of primers to one another or to nonspecific regions of the template.

Michael R. Green

Papers

Common progenitor cells in mature B-cell malignancies: implications for therapy.

High levels of BACH2 associated with lower levels of BCL2 transcript abundance in t(14;18)(q21;q34) translocation positive non-Hodgkin's lymphoma

C URRENT OPINION Common progenitor cells in mature B-cell malignancies: implications for therapy

Transformation of Escherichia coli by Electroporation

Hot Start Polymerase Chain Reaction (PCR)