| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1985: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
This study was performed to characterize a new calmodulin-binding protein, which was first identified and termed as CALSPERMIN by us, and to elucidate its biological significance. The results obtained are as follows;
1. Calspermin is a heat- and acid-stable calmodulin-binding protein which calcium-dependently interacts with calmodulin in one to one stoichiometry. Because of this property, calspermin inhibited calmodulinsupported cyclic nucleotide phosphodiesterase activation with Ki = 2.07 nM. Its molecular weight was 32,000, PI 3.9, <S_(20,w)> 1.43S, diffusion constant 5.4 <10^(-7)> <cm^2> /S, and f/ <f_o> 1.89.
2. The activity of calspermin as the inhibitor of calmodulin-supported cyclic nucleotide phosphodiesterase increased coincidently with the initiation of the second meiosis during the development of rat testis, and decreased gradually in parallel with the progression of testicular atrophy induced by hypophysectomy or surgical cryptorchidism. This change was paralleled by the simi
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lar change in calmodulin activity. The results suggested that calspermin may be involved in the regulation of meiosis, cell differentiation and/or sperm motility.
3. The immunoreactivity of rat testis calspermin to the specific antiserum against porcine testis calspermin differed from that of porcine testis calspermin. This indicates the immunological difference between rat tesits calspermin and porcine testis calspermin, though they are indistinguishable physicochemically.
4. Using this antiserum, we established a radioimmunoassay system and examined tissue distribution of calspermin in various porcine tissues. The calspermin content was high in testis, sperm and in central nervous system. In the latter, the content was high in gray matter of cerebral and cerebellar cortexes and in the granular layer of cerebellum, but that of white matter was considerably low.
5. In immunocytochemical study, strong immunostaining was observed in spermatocytes, sperm, gray matter of cerebral and cerebellar cortexes, as suggested by the results of radioimmunoassay. Moreover, the staining was obtained in some of neural cells present in several nuclei, but not in white matter. Thus, in central nervous system, calspermin appeared to be confined in the neural cells. Less
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