Mouse ZAR1-like (XM_359149) colocalizes with mRNA processing components and its dominant-negative mutant caused two-cell-stage embryonic arrest.

Maternal effect genes and encoding proteins are necessary for nuclear reprogramming and zygotic genome activation. However, the mechanisms that mediate these functions are largely unknown. Here we identified XM_359149, a Zar1-like gene that is predominantly expressed in oocytes and zygotes, which we designated Zar1-like (Zar1l). ZAR1L-EGFP formed multiple cytoplasmic foci in late two-cell-stage embryos. Expression of the ZAR1L C-terminus induced two-cell-stage embryonic arrest, accompanied with abnormal methylation of histone H3K4me2/3 and H3K9me2/3, and marked down-regulation of a group of chromatin modification factors including Dppa2, Dppa4, and Piwil2. When ectopically expressed in somatic cells, ZAR1L colocalized with P-body components including EIF2C1(AGO1), EIF2C2(AGO2), DDX6 and LSM14A, and germline-specific chromatoid body components including PIWIL1, PIWIL2, and LIN28. ZAR1L colocalized with ZAR1 and interacted with human LIN28. Our data suggest that ZAR1L and ZAR1 may comprise a novel family of processing-body/chromatoid-body components that potentially function as RNA regulators in early embryos.