A MEIG1/PACRG complex in the manchette is essential for building the sperm flagella.
Bottom Line: 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.PACRG is not stable in mammalian cells, but can be stabilized by MEIG1 or by inhibition of proteasome function.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.
Affiliation: Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA 23298, USA.Show MeSH
Mentions: MEIG1 interacts with the C-terminal region of SPAG16 protein (Zhang et al., 2004). The meiotically expressed SPAG16L is localized in the cytoplasm of spermatocytes (Zhang et al., 2004; Nagarkatti-Gude et al., 2011) and subsequently incorporated into the sperm flagella central apparatus, and is essential for sperm motility. To determine whether SPAG16L redistribution is dependent on MEIG1, we examined localization of SPAG16L in the elongating spermatids isolated from wild-type mice and Meig1-deficient mice. Not surprisingly, even though SPAG16L is localized in the cytoplasm of spermatocytes, in the elongating spermatids, it is localized in the manchette (upper panel of Fig. 6A). However, SPAG16L is no longer concentrated in the manchette of elongating spermatids from Meig1-deficient mice, but instead it is present in the whole cytoplasm (middle panel of Fig. 6A; supplementary material Fig. S3A,B). SPAG16L localization was also examined in the Pacrg-deficient mice. Similarly, SPAG16L is present throughout the whole cell body of the surviving elongating spermatids of Pacrg-deficient mice (lower panel of Fig. 6A; supplementary material Fig. S3C). However, the localization of both MEIG1 and PACRG in the elongating spermatids is not changed in the Spag16L-deficient mice (Fig. 6B).Fig. 6.
Affiliation: Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA 23298, USA.