McLaughlin E A, Frayne J, Barker H L, Jury J A, Jones R, Ford W C, Hall L
University Department of Obstetrics and Gynaecology, St. Michael's Hospital, Bristol, UK.
Mol Hum Reprod. 1997 Sep;3(9):801-9. doi: 10.1093/molehr/3.9.801.
Fertilin alpha and beta are members of the MDC (metalloproteinase-like, disintegrin-like, cysteine-rich) protein family and are expressed on the sperm surface where they have been proposed to play a role in mammalian fertilization. Inhibition of sperm-oocyte binding and sperm-oocyte fusion make fertilin an attractive target for the development of an immunocontraceptive vaccine. Full-length cDNAs encoding alpha and beta fertilin subunits were isolated from a rat testis cDNA library and sequenced. Using reverse transcription-polymerase chain reaction (RT-PCR), the developmental expression of fertilin alpha and beta was determined in pre-pubertal and mature rat testes. Fertilin alpha mRNA was present at all stages of development, suggesting that it is not exclusively expressed in post-meiotic germ cells. In contrast, fertilin beta mRNA was first identified in day 19 testes, coincident with the presence of pachytene spermatocytes. Polyclonal antisera raised against a 28-residue peptide (corresponding to part of the disintegrin domain) and two recombinant fusion proteins identified a 90 kDa protein in testicular sperm extracts and a 60 kDa protein in caput and cauda epididymidal sperm extracts, the predicted sizes for rat fertilin beta precursor and mature protein respectively. Indirect immunofluorescence using the anti-peptide antisera stained the acrosomal cap of permeabilized testicular, caput and caudal spermatozoa and elongating spermatids in testicular sections.
受精素α和β是MDC（金属蛋白酶样、解整合素样、富含半胱氨酸）蛋白家族的成员，在精子表面表达，据推测它们在哺乳动物受精过程中发挥作用。抑制精子与卵母细胞的结合以及精子与卵母细胞的融合，使得受精素成为开发免疫避孕疫苗的一个有吸引力的靶点。从大鼠睾丸cDNA文库中分离出编码受精素α和β亚基的全长cDNA并进行测序。利用逆转录-聚合酶链反应（RT-PCR），测定了青春期前和成熟大鼠睾丸中受精素α和β的发育表达情况。受精素α mRNA在发育的各个阶段均有表达，这表明它并非仅在减数分裂后的生殖细胞中表达。相比之下，受精素β mRNA首次在19日龄的睾丸中被鉴定出来，与粗线期精母细胞的出现时间一致。针对一个28个氨基酸残基的肽段（对应于解整合素结构域的一部分）和两种重组融合蛋白产生的多克隆抗血清，在睾丸精子提取物中鉴定出一种90 kDa的蛋白，在附睾头和附睾尾精子提取物中鉴定出一种60 kDa的蛋白，分别为大鼠受精素β前体和成熟蛋白的预测大小。使用抗肽抗血清进行间接免疫荧光染色，可对经通透处理的睾丸、附睾头和附睾尾精子的顶体帽以及睾丸切片中正在伸长的精子细胞进行染色。
