MEIG1 is essential for spermiogenesis in mice

Departments of Obstetrics and Gynecology and Biochemistry, Virginia Commonwealth University, Richmond, VA 23298, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 10/2009; 106(40):17055-60. DOI: 10.1073/pnas.0906414106
Source: PubMed


Spermatogenesis can be divided into three stages: spermatogonial mitosis, meiosis of spermatocytes, and spermiogenesis. During spermiogenesis, spermatids undergo dramatic morphological changes including formation of a flagellum and chromosomal packaging and condensation of the nucleus into the sperm head. The genes regulating the latter processes are largely unknown. We previously discovered that a bi-functional gene, Spag16, is essential for spermatogenesis. SPAG16S, the 35 kDa, testis-specific isoform derived from the Spag16 gene, was found to bind to meiosis expressed gene 1 product (MEIG1), a protein originally thought to play a role in meiosis. We inactivated the Meig1 gene and, unexpectedly, found that Meig1 mutant male mice had no obvious defect in meiosis, but were sterile as a result of impaired spermatogenesis at the stage of elongation and condensation. Transmission electron microscopy revealed that the manchette, a microtubular organelle essential for sperm head and flagellar formation was disrupted in spermatids of MEIG1-deficient mice. We also found that MEIG1 associates with the Parkin co-regulated gene (PACRG) protein, and that testicular PACRG protein is reduced in MEIG1-deficient mice. PACRG is thought to play a key role in assembly of the axonemes/flagella and the reproductive phenotype of Pacrg-deficient mice mirrors that of the Meig1 mutant mice. Our findings reveal a critical role for the MEIG1/PARCG partnership in manchette structure and function and the control of spermiogenesis.

Full-text preview

Available from:
  • Source
    • "PACRG/pEGFPC1 was constructed previously (Zhang et al., 2009). To clone mouse Pacrg cDNA into pCS2+MT vector, full-length mouse Pacrg cDNA was amplified using the following primers: forward, 5′-GAATT- CAAATGCCGAAGAGGACTAAACTG-3′; reverse, 5′-CTCGAGTCAG- TTCAGCAAGCACGACTC-3′. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A key event in the process of spermiogenesis is the formation of the flagella, which enables sperm to reach eggs for fertilization. Yeast two-hybrid studies revealed that meiosis-expressed gene 1 (MEIG1) and Parkin co-regulated gene (PACRG) interact, and that sperm-associated antigen 16, which encodes an axoneme central apparatus protein, is also a binding partner of MEIG1. In spermatocytes of wild-type mice, MEIG1 is expressed in the whole germ cell bodies, but the protein migrates to the manchette, a unique structure at the base of elongating spermatid that directs formation of the flagella. In the elongating spermatids of wild-type mice, PACRG colocalizes with α-tubulin, a marker for the manchette, whereas this localization was not changed in the few remaining elongating spermatids of Meig1-deficient mice. In addition, MEIG1 no longer localizes to the manchette in the remaining elongating spermatids of Pacrg-deficient mice, indicating that PACRG recruits MEIG1 to the manchette. PACRG is not stable in mammalian cells, but can be stabilized by MEIG1 or by inhibition of proteasome function. SPAG16L is present in the spermatocyte cytoplasm of wild-type mice, and in the manchette of elongating spermatids, but in the Meig1 or Pacrg-deficient mice, SPAG16L no longer localizes to the manchette. By contrast, MEIG1 and PACRG are still present in the manchette of Spag16L-deficient mice, indicating that SPAG16L is a downstream partner of these two proteins. Together, our studies demonstrate that MEIG1/PACRG forms a complex in the manchette and that this complex is necessary to transport cargos, such as SPAG16L, to build the sperm flagella. © 2015. Published by The Company of Biologists Ltd.
    Development 03/2015; 142(5):921-30. DOI:10.1242/dev.119834 · 6.46 Impact Factor
  • Source
    • "During the last two decades, the development of gene targeting technique in mice helped researchers to identify plenty of genes that are critical for normal spermiogenesis [1], [5]. Among them are genes essential for nuclear condensation and head shaping (e.g., Hook1, Prm1, Prm2, Tnp1, and Tnp2) [6], [7], [8], [9], [10], acrosome development (e.g., Hrb, Gopc, and Csnk2a2) [11], [12], [13] and flagellum formation (e.g., Bbs2, Tektin-t, Akap4, Meig1, and Pacrg) [14], [15], [16], [17], [18]. Although some of these gene products were demonstrated to bind each other and function in a cooperative manner [17], [19], the exact molecular roles and network of these proteins are still elusive and need to be further investigated. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Mammalian spermatogenesis comprises three successive phases: mitosis phase, meiosis phase, and spermiogenesis. During spermiogenesis, round spermatid undergoes dramatic morphogenesis to give rise to mature spermatozoon, including the condensation and elongation of nucleus, development of acrosome, formation of flagellum, and removal of excessive cytoplasm. Although these transformations are well defined at the morphological level, the mechanisms underlying these intricate processes are largely unknown. Here, we report that Iqcg, which was previously characterized to be involved in a chromosome translocation of human leukemia, is highly expressed in the spermatogenesis of mice and localized to the manchette in developing spermatids. Iqcg knockout causes male infertility, due to severe defects of spermiogenesis and resultant total immobility of spermatozoa. The axoneme in the Iqcg knockout sperm flagellum is disorganized and hardly any typical ("9+2") pattern of microtubule arrangement could be found in Iqcg knockout spermatids. Iqcg interacts with calmodulin in a calcium dependent manner in the testis, suggesting that Iqcg may play a role through calcium signaling. Furthermore, cilia structures in the trachea and oviduct, as well as histological appearances of other major tissues, remain unchanged in the Iqcg knockout mice, suggesting that Iqcg is specifically required for spermiogenesis in mammals. These results might also provide new insights into the genetic causes of human infertility.
    PLoS ONE 05/2014; 9(5):e98053. DOI:10.1371/journal.pone.0098053 · 3.23 Impact Factor
  • Source
    • "During this phase, haploid spermatids undergo extensive cellular, molecular and morphological changes to form spermatozoa. Haploid, round spermatids differentiate into species-specific shaped spermatozoa, with dramatic morphological changes, including elongation and condensation of the nucleus, and formation of the flagellum (Zhang et al., 2009). Some essential genes for spermiogenesis or spermiation have been identified, but the underlying mechanisms remain largely unknown. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Haploid spermatids undergo extensive cellular, molecular and morphological changes to form spermatozoa during spermiogenesis. Abnormalities in these steps can lead to serious male fertility problems, from oligospermia to complete azoospermia. CHD5 is a chromatin-remodeling nuclear protein expressed almost exclusively in the brain and testis. Male Chd5 knockout (KO) mice have deregulated spermatogenesis, characterized by immature sloughing of spermatids, spermiation failure, disorganization of the spermatogenic cycle and abnormal head morphology in elongating spermatids. This results in the inappropriate placement and juxtaposition of germ cell types within the epithelium. Sperm that did enter the epididymis displayed irregular shaped sperm heads, and retained cytoplasmic components. These sperm also stained positively for acidic aniline, indicating improper removal of histones and lack of proper chromatin condensation. Electron microscopy showed that spermatids in the seminiferous tubules of Chd5 KO mice have extensive nuclear deformation, with irregular shaped heads of elongated spermatids, and lack the progression of chromatin condensation in an anterior-to-posterior direction. However, the mRNA expression levels of other important genes controlling spermatogenesis were not affected. Chd5 KO mice also showed decreased H4 hyperacetylation beginning at stage IX, step 9, which is vital for the histone-transition protein replacement in spermiogenesis. Our data indicate that CHD5 is required for normal spermiogenesis, especially for spermatid chromatin condensation.
    Mechanisms of development 02/2014; 131:35-46. DOI:10.1016/j.mod.2013.10.005 · 2.44 Impact Factor
Show more