Evidence against requirement of Ser41 and Ser45 for function of PU.1 -- molecular cloning of rat PU.1

A consensus genome of sika deer (Cervus nippon) and transcriptome analysis provided novel insights on the regulation mechanism of transcript factor in antler development

BACKGROUND

Sika deer (Cervus nippon) holds significance among cervids, with three genomes recently published. However, these genomes still contain hundreds of gaps and display significant discrepancies in continuity and accuracy. This poses challenges to functional genomics research and the selection of an appropriate reference genome. Thus, obtaining a high-quality reference genome is imperative to delve into functional genomics effectively.

FINDINGS

Here we report a high-quality consensus genome of male sika deer. All 34 chromosomes are assembled into single-contig pseudomolecules without any gaps, which is the most complete assembly. The genome size is 2.7G with 23,284 protein-coding genes. Comparative genomics analysis found that the genomes of sika deer and red deer are highly conserved, an approximately 2.4G collinear regions with up to 99% sequence similarity. Meanwhile, we observed the fusion of red deer's Chr23 and Chr4 during evolution, forming sika deer's Chr1. Additionally, we identified 607 transcription factors (TFs) that are involved in the regulation of antler development, including RUNX2, SOX6, SOX8, SOX9, PAX8, SIX2, SIX4, SIX6, SPI1, NFAC1, KLHL8, ZN710, JDP2, and TWST2, based on this consensus reference genome.

CONCLUSIONS

Our results indicated that we acquired a high-quality consensus reference genome. That provided valuable resources for understanding functional genomics. In addition, discovered the genetic basis of sika-red hybrid fertility and identified 607 significant TFs that impact antler development.

B-transferase with a Pro234Ser substitution acquires AB-transferase activity

A/B-Transferase is a glycosyltransferase that transfers a sugar substrate onto H-antigen, which is responsible for the synthesis of glycoprotein- and glycolipid-conjugates termed A/B-antigens. One polymorphism that causes the Pro234Ser substitution in B-transferase was recently found in a genotyping study, and might be cis-AB. In the present study, we analyzed the phenotypes arising from the enzymatic specificity of B-transferase with the Pro234Ser mutation. To evaluate the effect of the P234S mutation on enzymatic specificity, we generated an expression plasmid for B-transferase with Pro234Ser as well as A-transferase with Leu266Met, which is frequently found in cis-ABs. Transfection of B-transferase/P234S or A-transferase/L266M cDNA into HeLa cells, an O-blood group cell line, resulted in an AB-phenotype by absorption-elution testing and immunostaining, whereas A- and B-transferase-expressing HeLa cells exhibited only their own activity. Molecular simulation indicated that the P234S mutation causes a conformational change in the substrate pocket making it suitable for N-acetylgalactosamine.

Analysis of PU.1/ICSBP (IRF-8) complex formation with various PU.1 mutants: molecular cloning of rat Icsbp (Irf-8) cDNA

We isolated cDNA encoding a full-length Interferon (IFN) consensus sequence binding protein [Icsbp; also called IFN regulatory factor-8 (Irf-8)] from rat and analyzed interaction between ICSBP and PU.1, an Ets-family transcription factor regulating hematopoietic cell-specific promoters. Electrophoretic mobility shift assay indicated that PU.1 with deletion of the PEST domain could not bind to ICSBP, although loss of the PEST domain had no effect on DNA-binding ability of PU.1 itself. An amino-acid replacement of Ser147 by Ala of the PEST domain of PU.1 did not affect DNA-binding ability of PU.1 to form a binary complex, PU.1/DNA, but clearly decreased the ternary complex formation of PU.1/ICSBP/DNA. Phosphatase treatment of the ternary complex markedly decreased PU.1/ICSBP/DNA-complex formation. These results indicated that Ser147 of PU.1 is definitively required for forming a complex with ICSBP and phosphorylation of PU.1 and/or ICSBP is critical for formation of the ternary complex.

Mast cells acquire monocyte-specific gene expression and monocyte-like morphology by overproduction of PU.1

PU.1 is a myeloid- and lymphoid-specific transcription factor that belongs to the Ets family. Recently, we found that overproduction of PU.1 in mouse bone marrow-derived hemopoietic progenitor cells induced monocyte-specific gene expression and caused their monocyte-like morphological change. In the present study, PU.1 was overproduced by using retrovirus expression system in differentiated bone marrow-derived mast cells. By overexpression of PU.1, cell surface expression of MHC class II, CD11b, CD11c, and F4/80 was induced, accompanied by reduced expression of c-kit, a mast cell-specific marker. Morphology of PU.1-transfected cells was altered toward monocyte-like one. PU.1-overproducing cells acquired T cell stimulatory ability and showed an increase in response to LPS stimulation, while response through FcepsilonRI was markedly reduced by overproduction of PU.1. These results suggest that the differentiated mast cells still have potential to display monocytic features. When PU.1 was overproduced in a different type of mast cell, peritoneal mast cells, similar monocyte-like morphological change, and the expression of CD11b and F4/80 were induced. However, surface level of CD11c and MHC class II was not affected. These results indicate that the potential capacity to exhibit monocytic features is different between both the mast cells.