Sandwich ELISA, Biotin-labelled antibody
Store the complete kit at 2–8°C. Under these conditions, the kit is stable until the expiration date (see label on the box).
Limit of Detection
n = 8; CV = 4.1%
n = 7; CV = 5.1%
Cysteine-Rich Secretory Protein 1 (CRISP-1, AEG-like protein, ARP, Acidic epididymal glycoprotein homolog, AEGL1), 28.5 kDa epididymal protein, is a member of the cysteine-rich secretory proteins (CRISPs) family. This family of proteins is defined by the presence of 16 conserved cysteines that fold into two domains: a CAP domain, which has been implicated in cell-cell adhesion, and a CRISP domain, which has been shown to regulate several classes of ion channels across multiple species.
CRISPs show a strong expression bias to the mammalian male reproductive tract and the venom of poisonous reptiles. Within mammals, CRISPs are also expressed in lower levels within non-reproductive tissues including secretory glands, skeletal muscle, the spleen and the thymus. In the male reproductive tract CRISPs have been implicated in many aspects of male germ cell biology spanning haploid germ cell development, epididymal maturation, capacitation, motility and the actual processes of fertilization.
Human CRISP-1 is produced throughout the epididymis, whereupon it is incorporated into epididymosomes and presumably transferred onto the sperm surface. CRISP-1 was also detected as a soluble form in the seminal plasma.
The molecular mechanism of action of the mammalian CRISP proteins remains uknown, but certain non-mammalian CRISP proteins can block ion channels. CRISP-1 gene knockout mouse sperm showed reduced ability to fertilize ZP-intact and ZP-free eggs, suggesting the importance of CRISP-1 in sperm-egg fusion process. An additional role for CRISP-1 is to inhibit the uptake of ions, such as Ca2+, required for capacitation.
In the rat, CRISP-1 comprises two forms referred to as Proteins D and E. One difference between the D and E forms is an additional single O-linked N-acetyl galactosamine on an amino residue in protein E that is not present on D form. The studies demonstrate that the more abundant D form interacts with spermatozoa transiently, consistent with a capacitation-suppressing function, and the E form binds tightly and could act in the female reproductive tract.
Findings indicate vasectomy has an effect on CRISP-1 expression, because after vasectomy, the flux and composition of the epididymal fluid are modified. CRISP-1 was detected in the seminal plasma of normal and vasovasostomized men, but not in vasectomized individuals. The soluble concentration of CRISP-1 was significantly higher in the seminal plasma of vasovasostomized men when compared with normal men.
Moreover, another study has detected different levels of CRISP-1 in two types of azoospermia.
The seminal plasma samples from normospermic and nonobstructive azoospermic donors was CRISP-1 positive, whereas CRISP-1 was absent or present at low levels in samples from patients with obstructive azoospermia.
Areas of investigation: Reproduction