[The importance of the tactile hairs in domestic dogs and the problem of trimming these from an animal welfare perspective]. / Bedeutung der Tasthaare beim Haushund und Problematik des Abschneidens aus Sicht des Tierschutzes.

The vibrissae are part of a tactile sensory organ in the facial area of the domestic dog. Each of the stiff, long tactile hairs belongs to its own, sensitively innervated, specialized hair follicle. Its structure is very similar to a cat's whiskers. The authors found no scientific evidence of this organ being underdeveloped or regressed in the domestic dog. The importance of tactile hairs has not yet been scientifically proven for the domestic dog, however, it is evident that dogs react sensitively to the touch of their vibrissae and that these hairs fulfill protective functions including the protection of the eyes. Further functions are discussed in the literature.Anatomically and physiologically it is proven that tactile hairs are part of a sensory organ and clearly differ from the body fur. Without them, the sensory organ is not functional. Trimming the vibrissae is therefore not at all a cosmetic measure in the context of grooming but constitutes a temporary amputation. By disabling a sensory organ, the animal suffers from temporary physical damage representing considerable harm. Thus, cutting the tactile hairs of the domestic dog for esthetic reasons is prohibited according to German, Austrian, and Swiss Animal Welfare Act.

ErCas12a CRISPR-MAD7 for Model Generation in Human Cells, Mice, and Rats.

MAD7 is an engineered class 2 type V-A CRISPR-Cas (Cas12a/Cpf1) system isolated from Eubacterium rectale. Analogous to Cas9, it is an RNA-guided nuclease with demonstrated gene editing activity in Escherichia coli and yeast cells. Here, we report that MAD7 is capable of generating indels and fluorescent gene tagging of endogenous genes in human HCT116 and U2OS cancer cell lines, respectively. In addition, MAD7 is highly proficient in generating indels, small DNA insertions (23 bases), and larger integrations ranging from 1 to 14 kb in size in mouse and rat embryos, resulting in live-born transgenic animals. Due to the different protospacer adjacent motif requirement, small-guide RNA, and highly efficient targeted gene disruption and insertions, MAD7 can expand the CRISPR toolbox for genome enginnering across different systems and model organisms.

CRISPRs for Optimal Targeting: Delivery of CRISPR Components as DNA, RNA, and Protein into Cultured Cells and Single-Cell Embryos.

The rapid development of CRISPR technology greatly impacts the field of genetic engineering. The simplicity in design and generation of highly efficient CRISPR reagents allows more and more researchers to take on genome editing in different model systems in their own labs, even for those who found it daunting before. An active CRISPR complex contains a protein component (Cas9) and an RNA component (small guide RNA [sgRNA]), which can be delivered into cells in various formats. Cas9 can be introduced as a DNA expression plasmid, in vitro transcripts, or as a recombinant protein bound to the RNA portion in a ribonucleoprotein particle (RNP), whereas the sgRNA can be delivered either expressed as a DNA plasmid or as an in vitro transcript. Here we compared the different delivery methods in cultured cell lines as well as mouse and rat single-cell embryos and view the RNPs as the most convenient and efficient to use. We also report the detection of limited off-targeting in cells and embryos and discuss approaches to lower that chance. We hope that researchers new to CRISPR find our results helpful to their adaptation of the technology for optimal gene editing.