We determined the prevalence of influenza A virus in dogs in Taiwan and isolated A/canine/Taiwan/E01/2014. Molecular analysis indicated that this isolate was closely related to influenza A(H6N1) viruses circulating in Taiwan and harbored the E627K substitution in the polymerase basic 2 protein, which indicated its ability to replicate in mammalian species.

The first step of steroid biosynthesis is catalyzed by cytochrome P450scc, encoded by CYP11A1. To achieve steroidogenic tissue-specific inactivation of genes in vivo by the Cre-loxP approach, we used the 4.4-kb regulatory region of the human CYP11A1 gene to drive Cre recombinase expression in the tissues that produce steroids. The resulting SCC-Cre mice express high levels of Cre in the adrenal cortex and gonads at the same sites as that for the endogenous CYP11A1 expression. In addition, Cre activity was found in the diencephalon and midbrain. In the developing brain, the Cre activity was first detected in the embryonic day 10.5. Our study is the first to show that the 4.4-kb CYP11A1 promoter is transcriptionally active in the brain in vivo.

Chicken infectious anaemia (CIA) is a disease with a highly economic impact in the poultry industry. The infected chickens are characterized by aplastic anaemia and extreme immunosuppression, followed by the increased susceptibility to secondary infectious pathogens and suboptimal immune responses for vaccination. Commercially available CIA vaccines are routinely used in the breeders in Taiwan to protect their progeny with maternal-derived antibodies. However, CIA cases still occur in the field and little is known about the genetic characteristics of Taiwanese chicken anaemia viruses (CAVs). In this study, CAV DNA was detected in 72 of 137 flocks collected during 2010-2015. Among the PCR-positive samples, the coding regions of 51 CAVs were sequenced. Phylogenetic analysis of the VP1 gene revealed that, although most of Taiwanese CAVs belonged to genotypes II and III, some isolates were clustered into a novel genotype (genotype IV). Moreover, a Taiwanese isolate in this novel genotype IV appeared to be derived from a recombination event between genotypes II and III viruses. Five Taiwanese CAV isolates were highly similar to the vaccine strains, 26P4 or Del-Ros. Taken together, these results indicate that the sequences of CAVs in Taiwan are variable, and inter-genotypic recombination had occurred between viruses of different genotypes. Moreover, vaccine-like strains might induce clinical signs of CIA in chickens. Our findings could be useful for understanding the evolution of CAVs and development of a better control strategy for CIA.

CYP11A1 encodes the first enzyme of steroid biosynthesis, cytochrome P450scc. The expression of CYP11A1 in the nervous system allows neurosteroids to be synthesized de novo. In the classic steroidogenic tissues, adrenals and gonads, the key regulator controlling CYP11A1 expression is steroidogenic factor-1 (SF-1), but the transcriptional regulation of CYP11A1 in the brain is unclear. We recently used the 4.4-kb regulatory region of the human CYP11A1 gene to drive Cre recombinase expression in the diencephalon and midbrain. In this study, we characterized the regional-specific expression of Cre reporter in the SCC-Cre transgenic brain using a transient Cre/ROSA26R transgenic system. Mutation of either the upstream or proximal SF-1 binding site did not affect brain CYP11A1 promoter activity. The upstream SF-1 binding site, however, is required for CYP11A1 promoter function in the embryonic adrenals. The 3.8-kb promoter, like the 4.4-kb length promoter, directed Cre expression in the diencephalon, midbrain and olfactory epithelium, whereas Cre expression controlled by the 2.7-kb promoter was only observed in the caudal part of midbrain. This suggests that the 5'-flanking region between 3.8 and 2.7 kb contains a crucial element for activation of CYP11A1 promoter in the diencephalon, olfactory epithelium and the anterior part of midbrain. Thus we have identified regions of the promoter that control CYP11A1 expression in the brain and embryonic adrenals.