Novel marker for the onset of frontotemporal dementia: early increase in activity-dependent neuroprotective protein (ADNP) in the face of Tau mutation
Authors: Eliezer Giladi
Yotam Ophir
Illana Gozes
Yulie Schirer
Anna Malishkevich
Jada Lewis
Journal: PLoS ONE (2014)
Discipline: Multidisciplinary
Keywords: Tauopathy; Alzheimer's disease; frontotemporal dementias; alternative splicing; protein species
Affiliations: The Adams Super Center for Brain Studies, The Lily and Avraham Gildor Chair for the Investigation of Growth Factors, The Elton Laboratory for Neuroendocrinology, Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel., Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, Florida, United States of America.

Abstract:  Tauopathy, a major pathology in Alzheimer's disease, is also found in ~50% of frontotemporal dementias (FTDs). Tau transcript, a product of a single gene, undergoes alternative splicing to yield 6 protein species, each with either 3 or 4 microtubule binding repeat domains (tau 3R or 4R, associated with dynamic and stable microtubules, respectively). While the healthy human brain shows a 1/1 ratio of tau 3R/4R, this ratio may be dramatically changed in the FTD brain. We have previously discovered that activity-dependent neuroprotective protein (ADNP) is essential for brain formation in the mouse, with ADNP+/- mice exhibiting tauopathy, age-driven neurodegeneration and behavioral deficits. Here, in transgenic mice overexpressing a mutated tau 4R species, in the cerebral cortex but not in the cerebellum, we showed significantly increased ADNP expression (~3-fold transcripts) in the cerebral cortex of young transgenic mice (~disease onset), but not in the cerebellum, as compared to control littermates. The transgene-age-related increased ADNP expression paralleled augmented dynamic tau 3R transcript level compared to control littermates. Blocking mutated tau 4R transgene expression resulted in normalization of ADNP and tau 3R expression. ADNP was previously shown to be a member of the SWItch/Sucrose NonFermentable (SWI/SNF) chromatin remodeling complex. Here, Brahma (Brm), a component of the SWI/SNF complex regulating alternative splicing, showed a similar developmental expression pattern to ADNP. Immunoprecipitations further suggested Brm-ADNP interaction coupled to ADNP - polypyrimidine tract-binding protein (PTB)-associated splicing factor (PSF)-binding, with PSF being a direct regulator of tau transcript splicing. It should be noted that although we have shown a correlation between levels of ADNP and tau isoform expression three months of age, we are not presenting evidence of a direct link between the two. Future research into ADNP/tau relations is warranted. 

Retracted: No

PubPeer comments:
 In Fig. 3A of this paper, there are indications of band splicing for the ADNP row, most clearly for the rightmost band. One of the marvels of this particular Western Blot is that actin has been co-stained with (the rather larger) ADNP. As is conventional, molecular weight markers have been supplied - not. Actin is one of the most abundant proteins in your average cell. Is that also true of ADNP? Otherwise, how can simultaneous immunostaining provide sensible results? Hopefully, the painstaking calibration of the antibodies detecting these two very different proteins has been elaborated in the Materials and Methods? ![image] , 
 An actin gel is reused as protein in Fig. 1B and mRNA in Fig. 2B. The Methods says the mRNA was quantified by RT-PCR. Conventionally, the latter are presented as white bands on dark background. Conventionally, the lane markers are shown in the RT-PCR figure image as these are visualised at the same time as the sample bands. According to Wikipedia, https: en.wikipedia.org wiki PLOS_One * PLOS One only verifies whether experiments and data analysis were conducted rigorously * Well, were the experiments conducted rigorously in this case? And if not, why didnu2019t any of the editor or the referees notice? ![image] , 
 #1 There is more in Figure 3A. Some bands look much more similar than expected (red and blue boxes). Moreover, in 3A there are same actin bands as in 1B and 2B (orange boxes), as reported in #2. ![file] , 
 #2 The Actin band in Fig 2B and 3A are the same. The simplest explanation is that Fig 2B is mislabeled, or rather, someone picked the *Western Blot* to illustrate the differences in Tau 3R without noticing that another author had written in the text that *PCR-quantified mRNA* would illustrate the differences. ![file] As a corollary, it follows that Fig 3A is a version of Fig 1B: longer-exposed, and extended to include the DOX+ lane. Or if you prefer, 1B is a version of 3A, truncated for clarity of explanation. Anyway, this suggests that the vertical edges mentioned in comment #1 are innocent. , 
 #3 Common features in the background of bands: ![file] , 
 #5 OK, perhaps there is a problem. ![file] DOX lanes, enlarged: ![file] , 
 #5 #6 Thank you both for marking up these in-gel improprieties. I really should have checked for repeated elements in the background while preparing comment #1. It might soon be time to send a missive via the intarwebs to the Public Library of Science. They donu2019t seem to be able to stop this sort of stuff appearing in their journals, but nowadays they do appear to be better at post-publication research integrity investigations. We have established that Fig. 1B, 2B, and 3A all use the same actin control gel. Despite 2B being RNA while 1B and 3A are protein. 2B and 3A are essentially the same exposure, while 1B is a greyer shade of pale. What hasnu2019t been discussed yet is that the 1B and 3A actins both control for ADNP expression. But the two rows of ADNP bands are mostly the same (allowing for the differences in exposure) but partly different. In particular, the lane 5 band in 3A is fully saturated and comparable to the lane 7 band, while the lane 5 band is very faint in 1B relative to all other bands. ![image] ,