Human embryonic lung cells (HEL-R66) are of monkey origin

Generating and working with Drosophila cell cultures: Current challenges and opportunities

The use of Drosophila cell cultures has positively impacted both fundamental and biomedical research. The most widely used cell lines: Schneider, Kc, the CNS and imaginal disc lines continue to be the choice for many applications. Drosophila cell lines provide a homogenous source of cells suitable for biochemical experimentations, transcriptomics, functional genomics, and biomedical applications. They are amenable to RNA interference and serve as a platform for high-throughput screens to identify relevant candidate genes or drugs for any biological process. Currently, CRISPR-based functional genomics are also being developed for Drosophila cell lines. Even though many uniquely derived cell lines exist, cell genetic techniques such the transgenic UAS-GAL4-based Ras^V12 oncogene expression, CRISPR-Cas9 editing and recombination mediated cassette exchange are likely to drive the establishment of many more lines from specific tissues, cells, or genotypes. However, the pace of creating new lines is hindered by several factors inherent to working with Drosophila cell cultures: single cell cloning, optimal media formulations and culture conditions capable of supporting lines from novel tissue sources or genotypes. Moreover, even though many Drosophila cell lines are morphologically and transcriptionally distinct it may be necessary to implement a standard for Drosophila cell line authentication, ensuring the identity and purity of each cell line. Altogether, recent advances and a standardized authentication effort should improve the utility of Drosophila cell cultures as a relevant model for fundamental and biomedical research. This article is categorized under: Technologies > Analysis of Cell, Tissue, and Animal Phenotypes.

Evidence for a nuclear factor(s), IRF-1, mediating induction and silencing properties to human IFN-beta gene regulatory elements

Transcription of the human interferon-beta (IFN-beta) gene is induced by a variety of agents such as viruses, dsRNA and some cytokines. In this study, we describe a nuclear factor, termed interferon regulatory factor-1 (IRF-1), that is involved in the transcription of IFN-beta and possibly other genes. We demonstrate that IRF-1 functions in virus-induced transcription by interacting with previously identified, IFN-beta regulatory DNA elements. Our data suggest that IRF-1 participates in the transient formation of an induction-specific complex(es) with the regulatory elements. IRF-1 may also be involved in silencing the function of the SV40 enhancer juxtaposed to the regulatory elements in uninduced cells.

The seed stock concept and quality control for cell lines

Procedures for the characterization of cell culture lines are reviewed. It is recommended that seed stocks be developed and that major quality-control efforts be applied first to those holdings, with essential tests repeated on cultures from working or distribution stocks prepared subsequently. Steps are taken throughout to ensure absence of microbial contaminants. Mycoplasma are especially troublesome. Investigators need also to be aware of potential endogenous viruses which may be hazardous or interfere with interpretation of results. Cell line species and absolute identities are established by fluorescent antibody staining, by determination of isoenzyme profiles, and by cytogenetic analyses. Additional characterizations will vary with cell type but may include tests for specific products, cytoskeletal proteins, tissue specific antigens, or immunoglobulins. Credentials of lines added to a collection plus representative cultures can be returned to the originators for concurrence before distribution. Advisory committees may be established as circumstance dictates to provide additional expertise regarding quality control for the specific collection being developed.

Cross-contamination of cells in culture

Lists are presented of references to all known publications describing cell properties that serve to characterize (i) known strains of HeLa and purported human cell lines indicated as HeLa contaminants, (ii) strains of human cell lines contaminated with human but non-HeLa cells, and (iii) strains of cells contaminated by cells from one or more other species. Frequencies of cell cross-contaminations are cited and references are presented to relatively simple techniques that could serve to detect such contamination.