Biology subjects

Nan, N.

Publications and source records attributed to Nan, N..

3 recordsLinked to original sources

bioRxiv2026

The SoxC transcription factors regulate multiple early retinal lineages and function in parallel with Atoh7 to promote retinal ganglion cell genesis

Retinal development is orchestrated by a network of transcription factors that guide multipotent retinal progenitor cells (RPCs) to fate-committed lineages, ultimately producing seven major retinal cell classes. Among these, retinal ganglion cells (RGCs) serve as the sole output neurons of the retina, relaying visual and non-visual information to the brain. RGC specification requires a cascade of transcriptional regulators, including the basic helix-loop-helix (bHLH) factor Atoh7, which confers competence to RPCs, and Pou4f2 and Isl1, which drive terminal differentiation and subtype diversification. Previous studies demonstrate that the SoxC group transcription factors (Sox4, Sox11, and Sox12) are also involved in RGC genesis, but their precise integration into the Atoh7-driven regulatory hierarchy remains undefined. To address this question, we used the retina-specific Vsx2-Cre line to generate Sox4/Sox11 double conditional knockout (dcKO) and Sox4/Sox11/Atoh7 triple knockout (tKO) mice. Immunohistochemistry revealed profound lineage disruption and reduced progenitor proliferation and survival in both dcKO and tKO retinas; not only RGC genesis but also that of horizontal and amacrine (H&As) cells were severely compromised, whereas photoreceptor cells (PHCs) production increased. These results indicate that Sox4 and Sox11 are involved in the coordinated generation of the different early retinal lineages. Like the Atoh7-null retina, RGC precursors still formed in the SoxC dcKO retina, but their genesis was almost completely abolished in the tKO retina. Our findings indicate that the SoxC factors act in parallel with Atoh7 as a major upstream regulatory input to initiate RGC fate. Bulk RNA-seq revealed the SoxC-dependent transcriptional programs and signaling pathways and confirmed the lineage changes demonstrated by marker analysis. CUT&Tag analysis identified the genome-wide binding sites and thereby the target genes of Sox11, further illuminating the mechanisms underlying functions of the SoxC factors in multiple retinal cell states/types during development.

developmental biology↗

bioRxiv2025

Ustilaginoidea virens suppresses floral immunity through promoting GA biosynthesis by the effector SCRE9

Rice false smut caused by Ustilaginoidea virens has become one of the most important rice diseases. U. virens specifically infects rice florets through stamen filaments. However, it is mysterious how U. virens inhibits floral immunity for successful colonization. Here, we show that a small cysteine-rich effector SCRE9 is a key virulence factor in U. virens. Expression of SCRE9 in rice not only suppresses immune responses and false smut resistance, but also significantly increases expression of expansin and gibberellin (GA) biosynthetic genes and GA content in young rice panicles. We further demonstrate that OsSIP1 (SCRE9-interacting protein 1) in rice is targeted by SCRE9 and interacts with the OsMADS63 and OsMADS68 transcription factors that transcriptionally regulate the GA synthesis gene GA3ox1. Interestingly, the chloroplast-localized OsSIP1 recruits OsMADS63/68 into the chloroplast. SCRE9 causes OsSIP1 to be translocated into the nucleus, thereby releasing OsMADS63/68 from the chloroplast into the nucleus to promote GA3ox1 transcription. Therefore, SCRE9 promotes GA biosynthesis and expression of expansins in rice florets, thus loosening cell walls and overcoming the physical barrier during U. virens infection. The finding uncovers an unidentified floret infection strategy that offsets the deficiency in cell wall degrading ability in the unique floret colonizing fungus.

plant biology↗

bioRxiv2022

The shifting epigenetic landscape and roles of key transcription factors during early retinal cell differentiation

How the diverse neural cell types emerge from multipotent neural progenitor cells during central nervous system development remains poorly understood. Recent scRNA-seq studies have delineated the developmental trajectories of individual neural cell types in many neural systems including the neural retina. Further understanding of the formation of neural cell diversity requires knowledge about how the epigenetic landscape shifts along individual cell lineages and how key transcription factors regulate these changes. In this study, we dissect the changes in the epigenetic landscape during early retinal cell differentiation by scATAC-seq and identify globally the enhancers, enriched motifs, and potential interacting transcription factors underlying the cell state/type specific gene expression in individual lineages. Using CUT&Tag, we further identify the enhancers bound directly by four key transcription factors, Otx2, Atoh7, Pou4f2, and Isl1, and uncover their roles in shaping the epigenetic landscape and controlling gene expression in a sequential and combinatorial fashion along individual retinal cell lineages such as retinal ganglion cells (RGCs). Our results reveal a general paradigm in which transcription factors collaborate and compete to regulate the emergence of distinct retinal cell types such as RGCs from multipotent retinal progenitor cells (RPCs).

developmental biology↗