Ttc27, which has a homolog in Caenorhabitis elegans named TRD-1, is a gene encoding a tetratricopeptide repeat-containing protein. In C. elegans, TRD-1 is essential for cell fate determination in the germline and developing epidermis, suggesting Ttc27 may have similar functions in higher organisms [2]. It may also be involved in stem cell-related processes as its ortholog in planarians was found to affect stem cell-associated functions like tissue homeostasis, regeneration, and stem cell maintenance [3].

In a study on Alzheimer-related traits, an association was observed between Ttc27 and white matter hyperintensities (WMH), suggesting a potential role in the genetic basis of Alzheimer disease [1]. Additionally, in mouse brain, the expression of Ttc27 was downregulated in both the cortical and hippocampal regions following chronic constant hypoxia (CCH) and chronic intermittent hypoxia (CIH) [4].

In summary, Ttc27 seems to be involved in cell fate determination, stem cell-related functions, and may play a role in neurodegenerative diseases like Alzheimer disease and response to hypoxic conditions in the brain. Research in model organisms such as C. elegans, planarians, and mice has provided valuable insights into its functions, highlighting its importance in understanding various biological processes and disease mechanisms.

References:

1. Melville, Scott A, Buros, Jacqueline, Parrado, Antonio R, Saykin, Andrew J, Farrer, Lindsay A. 2012. Multiple loci influencing hippocampal degeneration identified by genome scan. In Annals of neurology, 72, 65-75. doi:10.1002/ana.23644. https://pubmed.ncbi.nlm.nih.gov/22745009/

2. Hughes, Samantha, Wilkinson, Henry, Gilbert, Sophie P R, Ding, Siyu Serena, Woollard, Alison. 2014. The C. elegans TPR Containing Protein, TRD-1, Regulates Cell Fate Choice in the Developing Germ Line and Epidermis. In PloS one, 9, e114998. doi:10.1371/journal.pone.0114998. https://pubmed.ncbi.nlm.nih.gov/25493563/

3. Labbé, Roselyne M, Irimia, Manuel, Currie, Ko W, Blencowe, Benjamin J, Pearson, Bret J. . A comparative transcriptomic analysis reveals conserved features of stem cell pluripotency in planarians and mammals. In Stem cells (Dayton, Ohio), 30, 1734-45. doi:10.1002/stem.1144. https://pubmed.ncbi.nlm.nih.gov/22696458/

4. Zhou, Dan, Wang, Jiyi, Zapala, Matthew A, Schork, Nicholas J, Haddad, Gabriel G. 2007. Gene expression in mouse brain following chronic hypoxia: role of sarcospan in glial cell death. In Physiological genomics, 32, 370-9. doi:. https://pubmed.ncbi.nlm.nih.gov/18056785/