Participation of the TBP-associated factors (TAFs) in cell differentiation.

The understanding of the mechanisms that regulate gene expression to establish differentiation programs and determine cell lineages, is one of the major challenges in Developmental Biology. Besides the participation of tissue-specific transcription factors and epigenetic processes, the role of general transcription factors has been ignored. Only in recent years, there have been scarce studies that address this issue. Here, we review the studies on the biological activity of some TATA-box binding protein (TBP)-associated factors (TAFs) during the proliferation of stem/progenitor cells and their involvement in cell differentiation. Particularly, the accumulated evidence suggests that TAF4, TAF4b, TAF7L, TAF8, TAF9, and TAF10, among others, participate in nervous system development, adipogenesis, myogenesis, and epidermal differentiation; while TAF1, TAF7, TAF15 may be involved in the regulation of stem cell proliferative abilities and cell cycle progression. On the other hand, evidence suggests that TBP variants such as TBPL1 and TBPL2 might be regulating some developmental processes such as germ cell maturation and differentiation, myogenesis, or ventral specification during development. Our analysis shows that it is necessary to study in greater depth the biological function of these factors and its participation in the assembly of specific transcription complexes that contribute to the differential gene expression that gives rise to the great diversity of cell types existing in an organism. The understanding of TAFs' regulation might lead to the development of new therapies for patients which suffer from mutations, alterations, and dysregulation of these essential elements of the transcriptional machinery.

Identification of the gene encoding the TATA box-binding protein-associated factor 1 (TAF1) and its putative role in the heat shock response in the protozoan parasite Entamoeba histolytica.

Transcription factor IID (TFIID) is a cornerstone in the transcription initiation in eukaryotes. It is composed of TBP and approximately 14 different subunits named TBP-associated factors (TAFs). TFIID has a key role in transcription of many genes involved in cell proliferation, cell growth, cell cycle, cell cycle checkpoint, and various other processes as well. Entamoeba histolytica, the protozoan parasite responsible for human amoebiasis, represents a major global health concern. Our research group has previously reported the genes coding the TATA box-binding protein (EhTBP) and TBP-related factor 1 (EhTRF1), which displayed different mRNA levels in trophozoites under different stress conditions. In this work, we identified the TBP-associated factor 1 (Ehtaf1) gene in the E. histolytica genome, which possess a well-conserved DUF domain and a Bromo domain located in the middle and C-terminus of the protein, respectively. The EhTAF1-DUF domain tertiary structure is similar to the corresponding HsTAF1 DUF domain. RT-qPCR experiments with RNA isolated from trophozoites harvested at different time points of the growth curve and under different stress conditions revealed that the Ehtaf1 gene was found slightly upregulated in the death phase of growth curve, but under heat shock stress, it was found upregulated 10 times, suggesting that Ehtaf1 might have an important role in the heat shock stress response. We also found that EhTAF1 is expressed in the nucleus and cytoplasm at 37 °C, but under heat shock stress, it is overexpressed in both the nucleus and cytoplasm, and partially colocalized with EhHSP70 in cytoplasm.

Expression of the histone chaperone SET/TAF-Iß during the strobilation process of Mesocestoides corti (Platyhelminthes, Cestoda).

The histone chaperone SET/TAF-Iß is implicated in processes of chromatin remodelling and gene expression regulation. It has been associated with the control of developmental processes, but little is known about its function in helminth parasites. In Mesocestoides corti, a partial cDNA sequence related to SET/TAF-Iß was isolated in a screening for genes differentially expressed in larvae (tetrathyridia) and adult worms. Here, the full-length coding sequence of the M. corti SET/TAF-Iß gene was analysed and the encoded protein (McSET/TAF) was compared with orthologous sequences, showing that McSET/TAF can be regarded as a SET/TAF-Iß family member, with a typical nucleosome-assembly protein (NAP) domain and an acidic tail. The expression patterns of the McSET/TAF gene and protein were investigated during the strobilation process by RT-qPCR, using a set of five reference genes, and by immunoblot and immunofluorescence, using monospecific polyclonal antibodies. A gradual increase in McSET/TAF transcripts and McSET/TAF protein was observed upon development induction by trypsin, demonstrating McSET/TAF differential expression during strobilation. These results provided the first evidence for the involvement of a protein from the NAP family of epigenetic effectors in the regulation of cestode development.

Avaliação da capacidade cardiorrespiratória (vo2máx) em policiais militares, com testes indiretos / Assessment of cardiorespiratory fitness (VO2máx) in the military police of, with indirect tests

O objetivo deste estudo foi avaliar o (VO2máx) de militares com testes indiretos de 1600m (ALMEIDA et al., 2010) e 12min (COOPER,1968). Participaram 49 militares masculinos, aptos fisicamente, média de idade de 25,6 ±3,10 anos, IMC 23 ±1,4 Kg.m2, selecionados aleatoriamente. O (VO2máx) foi mensurado através das equações de Cooper e Almeida após os testes; coletados e analisados os parâmetros fisiológicos: frequência cardíaca, glicemia e lactato pré e pós-testes e percepção subjetiva do esforço ao final. Observou-se grande fidedignidade entre eles, sendo o valor do (VO2máx) de 1600m (43,63±3,21) superior ao de 12min (39,42±4,18), mostrando aumento significativo (p<0,0001), atribuída à potência de exercício desenvolvida durante o teste, que pode ser observada nos valores de lactato no de 1600m. A prova de 1600m, mostrou-se como uma alternativa eficaz na mensuração do (VO2máx) em militares, portanto sendo uma medida indireta de baixo custo e fácil uso e de grande valia sua aplicabilidade nas Instituições Militares.

The objective of this research was to evaluate the (VO2máx), in indirect tests of 1600m (Almeida et al., 2010) and 12 min (Cooper, 1968). 49 physically fit military aged 25.6±3.10 years, BMI23±1.4 kg.m2, where randomly chosen according to the inclusion criteria of the research took part of it. The (VO2máx) was measured through COOPER and Almeida equations after the tests of 1600m and 12min run, collected and analyzed physiological parameters of cardiac frequency glycemia and lactate were collected before and after the tests. Besides, the subjective perception of effort at the end of each test was evaluated. Through the physiological parameters, it could be observed a great reliability between the 1600m and 12min run tests, in which the (vo2máx) value in the former (43.63±3.21) was higher than in the latter test (39.42±4.18), showing a significant incriase (p<0.0001), attributed to the power developedduring the exercise test, which can be observed for lactate in the 1600m. The 1600m test, proved to be an effective alternative in measuring (vo2máx) in milytary, being an indirect measure of cost and ease of use and great value for their applicability in the military institutions.