Murine polo like kinase 1 gene is expressed in meiotic testicular germ cells and oocytes

Abstract

To identify key molecules that regulate germ cell proliferation and differentiation, we have attempted to isolate protein kinase genes preferentially expressed in germ line cells. One such cDNA cloned from murine embryonic germ(EG) cells encodes a nonreceptor type serine/threonine kinase and is predominantly expressed in the testis, ovary, and spleen of adult mouse. The nucleotide sequence of the entire coding regions shows that this clone, designated Plk1(polo like kinase 1), is identical with STPK13 previously cloned from murine erythro-leukemia cells. The protein encoded by Plk1 is closely related to the product of Drosophila polo that plays a role in mitosis and meiosis. To define the role of Plk1 in germ cell development, we have examined its expression in murine gonads by in situ hybridization. Here we show that the Plk1 gene is specifically expressed in spermatocytes of diplotene and diakinesis stage, in secondary spermatocytes, and in round spermatids in testes. It is also expressed in growing oocytes and ovulated eggs. The pattern of expression of the Plk1 gene suggests that the gene product is involved in completion of meiotic division, and like the Drosophila polo protein, is a maternal factor active in embryos at the early cleavage stage.

Rat Pachytene Spermatocytes Down-Regulate a Polo-Like Kinase and Up-Regulate a Thiol-Specific Antioxidant Protein, Whereas Sertoli Cells Down-Regulate a Phosphodiesterase and Up-Regulate an Oxidative Stress Protein after Exposure to Methoxyethanol and Methoxyacetic Acid

“…An intriguing observation to emerge from this study is that the cells most sensitive to ME or MAA are the spermatocytes entering diplotene and the first meiotic division (stages XIII and XIV). A polo-like kinase-1 gene has been shown to be specifically expressed in the diplotene and diakinesis stages of meiotic prophase (34,35). Like the Drosophila polo-like kinase, the Plk-1 enzyme is believed to play an important role in meiosis, with an involvement in the regulation of microtubule organization and consequent spindle formation.…”

The Transcriptional Program of Sporulation in Budding Yeast

“…A mammalian homolog of CDC5 is induced specifically during spermatogenesis (44). Two genes that are predicted to encode F-box proteins (45), YDR219 and YLR368, were induced midway through sporulation, raising the intriguing possibility that an SCF-like ubiquitin-conjugating complex may be necessary for progression through meiosis.…”

Differential regulation of polo-like kinase 1, 2, 3, and 4 gene expression in mammalian cells and tissues

“…Plk1 is expressed at the highest levels in tissues with actively proliferating cell populations; for example, the placenta (Golsteyn et al, 1994;Hamanaka et al, 1994;Holtrich et al, 1994;Takai et al, 1999;Yoshimatsu et al, 1999;Wolf et al, 2000), spleen (Clay et al, 1993;Lake and Jelinek, 1993;Golsteyn et al, 1994), ovary (Lake and Jelinek, 1993;Golsteyn et al, 1994;Hamanaka et al, 1994;Matsubara et al, 1995;Takai et al, 1999), and testis (Lake and Jelinek, 1993;Golsteyn et al, 1994;Matsubara et al, 1995;Syed and Hecht, 1998). Indeed, Northern blot hybridization experiments have shown that Plk1 transcripts are either undetectable or present at very low levels in most other adult tissues, including the liver, kidney, brain, thymus, intestine, lung, pancreas, heart, stomach, and skin (Clay et al, 1993;Lake and Jelinek, 1993;Golsteyn et al, 1994;Hamanaka et al, 1994;Holtrich et al, 1994;Georgescu et al, 1997;Wolf et al, 2000).…”