Human AGPAT6 peptide

Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the first committed step of de novo triacylglycerol synthesis by converting glycerol-3-phosphate to lysophosphatidic acid (LPA). LPA is a mitogen that mediates multiple cellular processes including cell proliferation. Four GPAT isoforms have been cloned to date. GPAT4 is strongly expressed in the mouse testis. Reverse transcription-polymerase chain reaction (PCR), real-time PCR, and in situ hybridization (ISH) were used to analyze the GPAT4 expression and to localize the expressing cell types in the mouse testis during postnatal development. GPAT4 cDNA was inserted into pcDNA4/His to construct a recombinant vector, which was transfected into a mouse spermatogonial cell line (GC-1spg). GPAT4 was first expressed in mice at 2 weeks postnatally. Expression was abundant from the third week, plateaued at week 5-6 and then maintained at a high level in the adult. ISH revealed that GPAT4 gene was expressed abundantly in spermatocytes and around spermatids during meiosis but not in elongated spermatids during later spermiogenesis. GC-1spg cells showed a marked increase in proliferation after transfection with GPAT4; cell cycle analysis showed a decrease in the percentage of cells in the G(0)/G(1) phase and an increase in the S phase. Thus, GPAT4 might play an important role in spermatogenesis, especially in mid-meiosis.

In a previous study, we identified candidate causative variants located in 24 functional candidate genes for milk protein and fatty acid composition in Montbeliarde, Normande, and Holstein cows. We designed these variants on the custom part of the EuroG10K BeadChip (Illumina Inc., San Diego, CA), which is routinely used for genomic selection analyses in French dairy cattle. To validate the effects of these candidate variants on milk composition and to estimate their effects on cheesemaking properties, a genome-wide association study was performed on milk protein, fatty acid and mineral composition, as well as on 9 cheesemaking traits (3 laboratory cheese yields, 5 coagulation traits, and milk pH). All the traits were predicted from midinfrared spectra in the Montbeliarde cow population of the Franche-Comte region. A total of 194 candidate variants located in 24 genes and 17 genomic regions were imputed on 19,862 cows with phenotypes and genotyped with either the BovineSNP50 (Illumina Inc.) or the EuroG10K BeadChip. We then tested the effect of each SNP in a mixed linear model including random polygenic effects estimated with a genomic relationship matrix. We confirm here the effects of candidate causative variants located in 17 functional candidate genes on both cheesemaking properties and milk composition traits. In each candidate gene, we identified the most plausible causative variant: 4 are missense in the ALPL, SLC26A4, CSN3, and SCD genes, 7 are located in 5' UTR (AGPAT6), 3' untranslated region (GPT), or upstream (CSN1S1, CSN1S2, PAEP, DGAT1, and PICALM) regions, and 6 are located in introns of the SLC37A1, MGST1, CSN2, BRI3BP, FASN, and ANKH genes.