Chromomycin A3 (CMA3) staining: The fluorescent dye of CMA3 is competing with protamine for binding to minor grooves of DNA which have CG-rich areas and therefore, indirectly shows the amount of protamine deficiency in the chromatin structure.
According to the CMA3 test, the percentage of sperm with protamine defect increased in group I (14.62[+ or -]4.53) and II (10.37[+ or -]2.44) in comparison to group III (9.0[+ or -]2.07) and there was no difference between groups I and II (Figure 2).
Human protamines and the developing spermatid: their structure, function, expression and relationship with ma le iniertility.
Relationships between human sperm protamines. DNA damage and assisted reproduction outcomes.
Diazinon alters sperm chromatin structure in mice by phosphorylating nuclear protamines. Toxicol.
Identification and evaluation of a novel sperm protamine abnormality in a population of infertile males.
The histones should be replaced by protamines during sperm DNA packaging for more chromatin condensation (39).
The Acidic Aniline Blue (AAB) stain discriminates between lysine-rich histones and arginine/cysteine-rich protamines. This stain specifically reacts with lysine residues in nuclear histones and reveals differences in the basic nuclear protein composition of the sperm.
There are three types of protamines : protamine 1 (P1),which forms the major component of sperm DNA binding protamines; protamine 2 (P2),which is deficient in cysteine residues and is expressed in spermatids prior to the widespread displacement of histones by transition proteins.
During spermatogenesis and epididymal transit, nuclear histones are replaced by arginine/cysteine rich protamines (10).
Chicken blood smears (Gallus domesticus) were also used as a representative reference tissue for evaluating acid extraction procedures and thereby establishing an operational definition for histone proteins and protamines (Alfert 1956).
A modified protocol of the Sakaguchi histochemical reaction for arginine (Barka & Anderson 1965) was used to assess alteration of histone proteins to arginine-rich protamines during spermiogenesis in lycosid spiders.
Nucleohistone from calf thymus, histone-free
protamine from salmon, salmon testis nucleoprotamine and ubiquitin from bovine red cells were also obtained from Sigma.
On the basis of these early studies, Bloch proposed an initial classification of SNBPs that distinguished five major groups: (1) The Salmo type consisting of relatively small arginine-rich "monoprotamines" found in fish such as salmon; (2) the mouse/grasshopper type consisting of cysteine-containing arginine-rich "stable
protamines"; (3) the Mytilus type, with proteins intermediate between those of
protamines and histones with respect to composition of arginine and lysine; (4) the Rana type in which mature sperm retains somatic-like chromosomal proteins; and (5) the crab type in which the DNA in the mature sperm apparently lacks any chromosomal proteins and as a result the nucleus appears large and swollen.
A
protamine deficiency appeared to affect fertilization rate and embryo quality.
