Although the CRISPR/Cas9/sgRNA system efficiently cleaves intracellular DNA at desired target sites, major concerns remain on potential “off-target” cleavage that may occur throughout the whole genome. In order to improve CRISPR-Cas9 specificity for targeted genome editing and transcriptional control, we describe a bioinformatics tool “sgRNAcas9”, which is a software package developed for fast design of CRISPR sgRNA with minimized off-target effects. This package consists of programs to perform a search for CRISPR target sites (protospacers) with user-defined parameters, predict genome-wide Cas9 potential off-target cleavage sites (POT), classify the POT into three categories, batch-design oligonucleotides for constructing 20-nt (nucleotides) or truncated sgRNA expression vectors, extract desired length nucleotide sequences flanking the on- or off-target cleavage sites for designing PCR primer pairs to validate the mutations by T7E1 cleavage assay. Importantly, by identifying potential off-target sites in silico, the sgRNAcas9 allows the selection of more specific target sites and aids the identification of bona fide off-target sites, significantly facilitating the design of sgRNA for genome editing applications. sgRNAcas9 software package is publicly available at BiooTools website (www.biootools.com) under the terms of the GNU General Public License.

Although the role of the epididymis, a male accessory sex organ, in sperm maturation has been established for nearly four decades, the maturation process itself has not been linked to a specific molecule of epididymal origin. Here we show that Bin1b, a rat epididymis-specific beta-defensin with antimicrobial activity, can bind to the sperm head in different regions of the epididymis with varied binding patterns. In addition, Bin1b-expressing cells, either of epididymal origin or from a Bin1b-transfected cell line, can induce progressive sperm motility in immotile immature sperm. This induction of motility is mediated by the Bin1b-induced uptake of Ca(2+), a mechanism that has a less prominent role in maintaining motility in mature sperm. In vivo antisense experiments show that suppressed expression of Bin1b results in reduced binding of Bin1b to caput sperm and in considerable attenuation of sperm motility and progressive movement. Thus, beta-defensin is important for the acquisition of sperm motility and the initiation of sperm maturation.