Rajbhandari, R. | bioRxiv Science

bioRxiv2023

Separation-of-function mutants reveal the NF-κB-independent involvement of IκBα in the regulation of stem cell and oncogenic programs

We previously demonstrated that the NF-{kappa}B inhibitor I{kappa}B binds the chromatin together with PRC2 to regulate a subset of developmental- and stem cell-related genes. This alternative function has been elusive in both physiological and disease conditions because of the predominant role of I{kappa}B as a negative regulator of NF-{kappa}B. We here uniquely characterize specific residues of I{kappa}B that allow the generation of separation-of-function (SOF) mutants that are defective for either NF-{kappa}B-related (SOF{Delta}NF-{kappa}B) or chromatin-related (SOF{Delta}H2A,H4) activities. Expression of I{kappa}B SOF{Delta}NF-{kappa}B, but not SOF{Delta}H2A/H4, is sufficient to negatively regulate a specific stemness program in intestinal cells, thus rescuing the differentiation blockage imposed by I{kappa}B deficiency. In contrast, full I{kappa}B activity is required for regulating clonogenic/tumor-initiating activity of colorectal cancer cells. Our data indicate that SOF mutants represent an exclusive tool for studying I{kappa}B functions in physiology and disease, and identified I{kappa}B as a robust prognosis biomarker for human cancer.

cell biology↗

bioRxiv2023

High prevalence of Bovine Tuberculosis reported in Cattle and Buffalo of Eastern Nepal

Livestock farming, specifically of cattle and buffalo, is crucial to Nepals economy, with more than 66% of the population involved in agriculture and animal husbandry. Animal tuberculosis (TB) caused by Mycobacterium bovis is a chronic disease that affects these animals and results in economic losses due to reduced milk and meat productivity, fertility and mortality. M. bovis also infects humans, non-human primates, goats and other mammals, and can afflict both cattle and buffalo. Our study is a part of routine surveillance of prevalent diseases, including M. bovis, in cattle and buffalo. We collected blood samples (n=400, 100 samples from each district) from selected eastern districts of Nepal. We used a Rapid Bovine TB Test Kit to test these samples for presence of M. bovis. Of the 400 samples collected, 74 animals (18.75%) tested positive for M. bovis, with the majority of positive samples coming from cattle (n=71, 17.75%) and only three from buffalo (<1%). Among the screened breeds of cattle and buffalo, Holstein Friesian cattle (HF) (n=43, 58%), Jersey-cross cattle (JX) (n=20, 27%), Local buffalo (n=8, 10.8%) and Murra breed buffalo (n=3, 4.1%) were found to carry M. bovis. The majority (50%) of infected animals were between 3-6 years old. Morang (n= 24 positive in cattle; n=1 positive in buffalo) and Jhapa (n= 22 positive in cattle; n=2 positive in buffalo) had the highest prevalence of M. bovis, while all the positive cases in Sunsari (n=19) and Udaypur (n=6) were in cattle. The fact that over 18% of the samples tested positive for M. bovis is of great concern. It is critical to thoroughly test animal products from these livestock prior to human consumption. To prevent and mitigate M. bovis-related infections in Nepal, a more comprehensive screening strategy coupled with more effective animal husbandry practices needs to be adapted.

microbiology↗