Recommendation of short tandem repeat profiling for authenticating human cell lines, stem cells, and tissues

Cell misidentification and cross-contamination have plagued biomedical research for as long as cells have been employed as research tools. Examples of misidentified cell lines continue to surface to this day. Efforts to eradicate the problem by raising awareness of the issue and by asking scientists voluntarily to take appropriate actions have not been successful. Unambiguous cell authentication is an essential step in the scientific process and should be an inherent consideration during peer review of papers submitted for publication or during review of grants submitted for funding. In order to facilitate proper identity testing, accurate, reliable, inexpensive, and standardized methods for authentication of cells and cell lines must be made available. To this end, an international team of scientists is, at this time, preparing a consensus standard on the authentication of human cells using short tandem repeat (STR) profiling. This standard, which will be submitted for review and approval as an American National Standard by the American National Standards Institute, will provide investigators guidance on the use of STR profiling for authenticating human cell lines. Such guidance will include methodological detail on the preparation of the DNA sample, the appropriate numbers and types of loci to be evaluated, and the interpretation and quality control of the results. Associated with the standard itself will be the establishment and maintenance of a public STR profile database under the auspices of the National Center for Biotechnology Information. The consensus standard is anticipated to be adopted by granting agencies and scientific journals as appropriate methodology for authenticating human cell lines, stem cells, and tissues.     

Life and death of a BiP substrate

BiP is the mammalian endoplasmic reticulum (ER) Hsp70 orthologue that plays a major role in all functions of this organelle including the seemingly opposing functions of aiding the maturation of unfolded nascent proteins and identifying and targeting chronically unfolded proteins for degradation. The recent identification of mammalian BiP co-factors combined with delineation of the ER degradation machinery and data suggesting that the ER is subdivided into unique regions helps explain how these different functions can occur in the same organelle and raises some unresolved issues.     

Age distribution of lactating New Zealand sea lions: Interannual and intersite variation

The age distribution of 865 lactating New Zealand sea lions (NZSLs; Phocarctos hookeri ) was investigated over 3 yr (1999–2001) at two breeding colonies, Sandy Bay and Dundas Island, New Zealand. Lactating females were aged between 3 and 26 yr with a maximum observed age of 28 yr. The mean age of lactating females was 11.1 (SE = 0.16) yr. Age distributions peaked at ages 8 and 9 with a strong skew toward younger females, likely indicative of maximum recruitment into the breeding population by this age. There were significant intersite differences in age structure and also significant interannual differences in age distributions at Sandy Bay, but not at Dundas Island. Given that the two colonies are less than 10 km apart, have some interchange, and share foraging areas, these differences are surprising. However, the colony at Dundas Island is almost four times larger than Sandy Bay and may therefore be less sensitive to demographic or environmental stochasticity. That age distributions of NZSLs vary significantly over small temporal and spatial scales has important implications for the extrapolation of data from one site or year to the population level, and hence for their management and conservation.     

Structural basis for apoptosis inhibition by Epstein-Barr virus BHRF1

Epstein-Barr virus (EBV) is associated with human malignancies, especially those affecting the B cell compartment such as Burkitt lymphoma. The virally encoded homolog of the mammalian pro-survival protein Bcl-2, BHRF1 contributes to viral infectivity and lymphomagenesis. In addition to the pro-apoptotic BH3-only protein Bim, its key target in lymphoid cells, BHRF1 also binds a selective sub-set of pro-apoptotic proteins (Bid, Puma, Bak) expressed by host cells. A consequence of BHRF1 expression is marked resistance to a range of cytotoxic agents and in particular, we show that its expression renders a mouse model of Burkitt lymphoma untreatable. As current small organic antagonists of Bcl-2 do not target BHRF1, the structures of it in complex with Bim or Bak shown here will be useful to guide efforts to target BHRF1 in EBV-associated malignancies, which are usually associated with poor clinical outcomes.     

Programmed anuclear cell death delimits platelet life span

Platelets are anuclear cytoplasmic fragments essential for blood clotting and wound healing. Despite much speculation, the factors determining their life span in the circulation are unknown. We show here that an intrinsic program for apoptosis controls platelet survival and dictates their life span. Pro-survival Bcl-x(L) constrains the pro-apoptotic activity of Bak to maintain platelet survival, but as Bcl-x(L) degrades, aged platelets are primed for cell death. Genetic ablation or pharmacological inactivation of Bcl-x(L) reduces platelet half-life and causes thrombocytopenia in a dose-dependent manner. Deletion of Bak corrects these defects, and platelets from Bak-deficient mice live longer than normal. Thus, platelets are, by default, genetically programmed to die by apoptosis. The antagonistic balance between Bcl-x(L) and Bak constitutes a molecular clock that determines platelet life span: this represents an important paradigm for cellular homeostasis, and has profound implications for the diagnosis and treatment of disorders that affect platelet number and function.     

Mitochondrial DNA and the peopling of South America

The initial peopling of South America is largely unresolved, in part because of the unique distribution of genetic diversity in native South Americans. On average, genetic diversity estimated within Andean populations is higher than that estimated within Amazonian populations. Yet there is less genetic differentiation estimated among Andean populations than estimated among Amazonian populations. One hypothesis is that this pattern is a product of independent migrations of genetically differentiated people into South America. A competing hypothesis is that there was a single migration followed by regional isolation. In this study we address these hypotheses using mtDNA hypervariable region 1 sequences representing 21 South American groups and include new data sets for four native Peruvian communities from Tupe, Yungay, and Puno. An analysis of variance that compared the combined data from western South America to the combined data from eastern South America determined that these two regional data sets are not significantly different. As a result, a migration from a single source population into South America serves as the simplest explanation of the data.     

Detection of prostate cancer in unselected young men: prospective cohort nested within a randomised controlled trial

Objective To investigate the feasibility of testing for prostate cancer and the prevalence and characteristics of the disease in unselected young men.Design Prospective cohort nested within a randomised controlled trial, with two years of follow-up.Setting Eight general practices in a UK city.Participants 1299 unselected men aged 45-49.Intervention Prostate biopsies for participants with a prostate specific antigen level of 1.5 ng/ml or more and the possibility of randomisation to three treatments for those with localised prostate cancer.Main outcome measures Uptake of testing for prostate specific antigen; positive predictive value of prostate specific antigen; and prevalence of prostate cancer, TNM disease stage, and histological grade (Gleason score).Results 442 of 1299 men agreed to be tested for prostate specific antigen (34%) and 54 (12%) had a raised level. The positive predictive value for prostate specific antigen was 21.3%. Ten cases of prostate cancer were detected (2.3%) with eight having at least two positive results in biopsy cores and three showing perineural invasion. One tumour was of high volume (cT2c), Gleason score 7, with a positive result on digital rectal examination; nine tumours were cT1c, Gleason score 6, and eight had a negative result on digital rectal examination. Five of the nine eligible participants (55%) agreed to be randomised. No biochemical disease progression in the form of a rising prostate specific antigen level occurred in two years of follow-up.Conclusions Men younger than 50 will accept testing for prostate cancer but at a much lower rate than older men. Using an age based threshold of 1.5 ng/ml, the prevalence of prostate cancer was similar to that in older men (3.0 ng/ml threshold) and some cancers of potential clinical significance were found.Trial registration Current Controlled Trials ISRCTN20141297