Maelstrom gene
The gene Maelstrom, Mael, creates a protein, which was first located in Drosophila melanogaster in the nuage perinuclear structure and has functionality analogous to the spindle, spn, gene class.[1]
Drosophila Maelstrom
Maelstrom helps establish anterior-posterior and dorsal-ventral symmetry by coordinating to the Microtubule-Organizing Center (MTOC) [2] and assists Vasa establish a concentration gradient of Bicaudal D (BicD)[1] in the developing Drosophila oocyte. Similar to other spindle-class genes, maelstrom defects can lead to the failed production of a karyosome.[1] Mael has also been shown to repress microRNA-7 (miR-7), which in turn regulates the Bag-of-marbles (BAM) protein and secures correct germline differentiation.[3]
Short RNAs are well-known to silence TEs (transposable elements) through the RNAi (RNA interference) pathway, and Piwi-associated RNAs (piRNAs) play a crucial role in transposon silencing in the germline. The Maelstrom protein forms a complex with piRISC to silence transposons and therefore stabilize the germline cell genome.[4]
Mammalian Homolog, MAEL
A knockout model for MAEL, the mammalian homolog of Drosophila’s Maelstrom, was created by homologous recombination in mice to create Mael null mice. In the knockout mice, meiotic chromosome synapsis is defective. In addition, spermatogenesis fails due to sperm DNA damage caused by the derepression of transposable elements.[5]
MAEL has also recently been associated with human cancer. An experiment showed MAEL expression throughout a majority of cancer cell types, including lung cancer, breast cancer, prostate cancer, and colon cancer and in turn suggests MAEL as a constituent of the cancer/testis gene class.[6]
References
- ^ a b c Findley SD, Tamanaha M, Clegg NJ, Ruohola-Baker H (2003). Maelstrom, a Drosophila spindle-class gene, encodes a protein that colocalizes with Vasa and RDE1/AGO1 homolog, Aubergine, in nuage. Dev. 130:859–871.
- ^ Sato K, Nishida KM, Shibuya A, Siomi MC, Siomi H (2011). Maelstrom coordinates microtubule organization during Drosophila oogenesis through interaction with components of the MTOC. Genes & Dev. 2011. 25: 2361-2373.
- ^ Pek JW, Lim AK, Kai T (2009). Drosophila Maelstrom ensures proper germline stem cell lineage differentiation by repressing microRNA-7. Dev. Cell. 17: 417-424.
- ^ Sokolova OA, Yakushev EY, Stolyarenko AD, Mikhaleva EA, Gvozdev VA, Klenov MS (2011). Interplay of transposon-silencing genes in the germline of Drosophila melanogaster. Molecular Biology. 45: 582-590.
- ^ Soper SF, van der Heijden GW, Hardiman TC, Goodheart M, Martin SL, de Boer P, Bortvin A (2008). Mouse maelstrom, a component of nuage, is essential for spermatogenesis and transposon repression in meiosis. Dev. Cell. 15:285–297.
- ^ Xiao L, Wang YJ, Zhou YK, Sun Y, Sun W, Wang L, Zhou C, Zhou JL, Zhou JA (2010). Identification of a novel human cancer/testis gene MAEL that is regulated by DNA methylation. Molecular Biology Reports. 37: 2355-2360.