Seasonal patterns of ornithine decarboxylase activity and levels of polyamines in relation to the cytology of germinal cells during spermatogenesis in the sea star, Asterias vulgaris

Watts, Stephen A.; Hines, Gene A.; Lee, K.; Jaffurs, Daniel; Roy, Jeremy; Smith, F. B.; Walker, Charles W.

doi:10.1016/0040-8166(90)90073-i

Cited by 9 publications

(3 citation statements)

References 33 publications

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“…A common denominator in both steroid and MAP‐kinase mitogenic pathways is expression of the c‐myc gene. Such expression, in turn, leads to expression of downstream cell cycle‐related genes and gene products, such as ornithine decarboxylase (ODC, the rate‐limiting enzyme in production of polyamines, which are essential components of S‐phase cytoplasm) 13 and cyclins (particularly C and D, which heterodimerize with appropriate CDKs related to phosphorylation of G1/S‐phase protein substrates, such as Rb and p53). 2 Using the testes of Asterias vulgaris , we have cloned the first eukaryotic, nonvertebrate homolog of the c‐myc protooncogene.…”

Section: Mitogenic Pathways Involved In Spermatogonial G1/s‐phase Tramentioning

confidence: 99%

Interacting Mitogenic Pathways during Spermatogonial G1/S‐Phase Traverse in the Sea Star, Asterias vulgaris^a

Walker

Demian

Kirby

et al. 1998

Annals of the New York Academy of Sciences

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Section: Mitogenic Pathways Involved In Spermatogonial G1/s‐phase Tramentioning

confidence: 99%

Interacting Mitogenic Pathways during Spermatogonial G1/S‐Phase Traverse in the Sea Star, Asterias vulgaris^a

Walker

Demian

Kirby

et al. 1998

Annals of the New York Academy of Sciences

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“…In field populations of A. vulgaris, spermatogenesis is initiated in the fall with a rapid increase in the mitotic activity of spermatogonia. There is a large increase in the expression of the c-myc proto-oncogene at this time (Walker et al, 1992) as well as concomitant increases in the activity of ornithine decarboxylase and the production of polyamines (Watts et al, 1990a). Significant increases in both proto-oncogene expression and tissue polyamine levels are indicative of proliferative cell growth.…”

Section: Starfish Spermatogenesismentioning

confidence: 99%

“…5). Using this spermatogenic system, recent work has focused on identifying the biochemical mechanisms that regu-late this seasonal pattern of cellular activity with studies on the cytology of spermatogenesis (Walker, 1980;Watts et al, 1990a), photoperiodic regulation (Pearse and Walker, 1986), annual patterns in ornithine decarboxylase activity and polyamine levels (Watts et al, 1990a), kinetics of ornithine decarboxylase (Watts et al, 1990b), steroid metabolism (Hines et al, 1992a,b), and proto-oncogene expression (Walker et al, 1992(Walker et al, , 1994. From these studies it is clear that there is an abrupt transition from cellular inactivity during summer to a sudden burst of cellular proliferation during fall.…”

Section: Introductionmentioning

confidence: 99%

Effect of estradiol and progesterone on c‐myc expression in the sea star testis and the seasonal regulation of spermatogenesis

Marsh

Walker

1995

Molecular Reproduction Devel

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Analysis of the expression of cell cycle control genes provides a sensitive assay for mitotic and meiotic progression under experimental conditions. Transcription of the c-myc proto-oncogene and thymidine incorporation into DNA were both used to assay the mitogenic effects of estradiol and progesterone on the testicular germinal epithelium of the starfish Asterias vulgaris. Experimental in vitro studies during the annual spermatogenic cycle show that testes are not sensitive to mitotic stimulation by estradiol alone, whereas progesterone alone is mitotically inhibitory. The germinal epithelium can only be mitotically stimulated by estradiol after pretreatment with progesterone. The net increase in mitotic activity following a progesterone to estradiol transfer is dependent on the length of progesterone pretreatment. Overall, the seasonal pattern of testicular estradiol and progesterone levels evident in field populations of A. vulgaris (Hines et al., 1992a: Endocrinology 100:1468-1471) do not appear to be responsible for initiating spermatogonial mitosis at the onset of the annual spermatogenic cycle. Expression rates of the c-myc proto-oncogene are substantially more sensitive than thymidine incorporation in quantifying mitotic activity. Measuring proto-oncogene expression provides an ideal experimental approach to investigations of the regulatory mechanisms that control growth and reproduction in marine organisms.

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Elevated ornithine decarboxylase activity and polyamine levels during early development in the brine shrimp Artemia franciscana

1994

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Rehydrated Artemia cysts were assayed for ornithine decarboxylase (ODC) activity and levels of putrescine, spermidine, and spermine during pre-emergent development, emergence and hatching. Low but detectable ODC activity levels increased significantly within 2 hr, suggesting de novo synthesis of ODC protein and representing one of the earliest enzymatic biochemical markers in post dormancy development. ODC activity increased 100-fold during preemergent development (occurring in the absence of an increase in tissue polyamine content). This increase in enzyme activity occurs in the relative absence of DNA synthesis but may be related to an enhanced polyamine synthetic capacity necessary for other physiological processes such as early transcriptional and translational activity. A second, higher ODC activity peak (correlated with a significant increase in polyamines) prior to hatching may be related to DNA synthesis and other biochemical processes associated with hatching of stage 1 nauplii and is correlated with increasing ecdysteroid titres reported previously. Putrescine and spermidine levels were significantly higher than spermine levels (2.5, 2.65, and 0.13 kmoles/g dry weight) at the onset of rehydration. High endogenous polyamines levels in encysted embryos are most likely available for use in metabolic processes associated with early differentiation. Polyamine levels increased significantly just prior to emergence and continued increasing throughout hatching. Spermidine to spermine ratios (>18) should reflect high rates of overall biosynthetic processes throughout preemergence, emergence, and hatching. 0 1994 Wiley-Liss, Inc.Early development in Artemia raised from cysts can be categorized into three distinct stages: preemergence (PED), emergence 1 and 2 ( E l and E2), and hatching of stage one nauplii (Nl) (Clegg and Conte, '80). PED is characterized by embryonic cell differentiation in the relative absence of cell division (Benesch, '69; McClean and Warner, '71). During PED cellular differentiation is accompanied by distinct changes in cellular biochemistry (Clegg and Conte, '80; Hultin and Nilsson, '80; Carpenter and Hand, '86a; Utterback and Hand, '87). Cell division occurs primarily during and after emergence, followed by a variety of morphological and physiological changes during emergence and hatching.The polyamines spermidine and spermine and their diamine precursor putrescine are the most abundant organic cations in eukaryotic cells. Polyamine function and metabolism in vertebrates has been reviewed (Heby, '81; Pegg and McCann, '82; Tabor and Tabor, '84; Russell, '85; Slotkin and Bartolome, '86; Pegg, '86, '88 involvement in cell proliferation, particularly as it applies to neoplastic cells and tumors.Polyamine synthesis is controlled by ornithine decarboxylase (ODC, EC 4.1.1.17), the initial and rate-limiting enzyme in polyamine production (reviewed by Russell, '85). ODC catalyses the conversion of L-ornithine to putrescine which is converted further to spermidine and spermine by the ad...

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Seasonal patterns of ornithine decarboxylase activity and levels of polyamines in relation to the cytology of germinal cells during spermatogenesis in the sea star, Asterias vulgaris

Cited by 9 publications

References 33 publications

Interacting Mitogenic Pathways during Spermatogonial G1/S‐Phase Traverse in the Sea Star, Asterias vulgaris^a

Interacting Mitogenic Pathways during Spermatogonial G1/S‐Phase Traverse in the Sea Star, Asterias vulgaris^a

Effect of estradiol and progesterone on c‐myc expression in the sea star testis and the seasonal regulation of spermatogenesis

Elevated ornithine decarboxylase activity and polyamine levels during early development in the brine shrimp Artemia franciscana

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Seasonal patterns of ornithine decarboxylase activity and levels of polyamines in relation to the cytology of germinal cells during spermatogenesis in the sea star, Asterias vulgaris

Cited by 9 publications

References 33 publications

Interacting Mitogenic Pathways during Spermatogonial G1/S‐Phase Traverse in the Sea Star, Asterias vulgarisa

Interacting Mitogenic Pathways during Spermatogonial G1/S‐Phase Traverse in the Sea Star, Asterias vulgarisa

Effect of estradiol and progesterone on c‐myc expression in the sea star testis and the seasonal regulation of spermatogenesis

Elevated ornithine decarboxylase activity and polyamine levels during early development in the brine shrimp Artemia franciscana

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Interacting Mitogenic Pathways during Spermatogonial G1/S‐Phase Traverse in the Sea Star, Asterias vulgaris^a

Interacting Mitogenic Pathways during Spermatogonial G1/S‐Phase Traverse in the Sea Star, Asterias vulgaris^a