Biomedical subjects

Kehui Shi

Publications and source records attributed to Kehui Shi.

3 recordsLinked to original sources

PubMed2006

Tob1 controls dorsal development of zebrafish embryos by antagonizing maternal beta-catenin transcriptional activity.

Maternal beta-catenin and Nodal signals are essential for the formation of the dorsal organizer, which, in turn, induces neural and other dorsal tissue development in vertebrate embryos. Tob (Transducer of ErbB2) proteins possess antiproliferative properties and are known to influence BMP signaling, but their relationship to other signaling pathways and to embryonic patterning in general was unclear. In this study, we demonstrate that zebrafish tob1a is required for correct dorsoventral patterning. Mechanistically, Tob1a inhibits beta-catenin transcriptional activity by physically associating with beta-catenin and preventing the formation of beta-catenin/LEF1 complexes. Although Tob1a can also inhibit the transcriptional activity of the Nodal effector Smad3, its role in limiting dorsal development is executed primarily by antagonizing the beta-catenin signal. We further demonstrate that Tob family members across species share similar biochemical properties and biological activities.

Animals↗

PubMed2004

Cloning and expression analysis of zebrafish tob1 gene.

Many members of the Btg/Tob family, which possess anti-proliferation activity, have been identified in mammals but their physiological functions are poorly understood. We have identified a zebrafish tob1 gene, which encodes a peptide of 322 amino acids. The expression pattern of zebrafish tob1 during early embryogenesis is examined by RT-PCR and whole-mount in situ hybridization. The maternal tob1 transcript is abundant in fertilized eggs and blastulas. The expression of tob1 ceases during midgastrulation and early segmentation, when it is expressed and restricted to the notochord and somites. On day 2, expression occurs in the pectoral fin bud but not in other tissues. It will be interesting to investigate whether Tob1 is required for controlling cell proliferation during vertebrate embryogenesis.

Amino Acid Sequence↗

PubMed2002

A novel zinc finger transcription factor resembles krox-20 in structure and in expression pattern in zebrafish.

Krx-20, a zinc finger protein, plays an essential role in hindbrain segmentation of vertebrates. Zebrafish gene frb35 encodes a novel zinc finger protein that shares a high homology with Krx-20. The expression domains of frb35 overlap those of krx-20. The expression of frb35 first occurs in the 3rd rhombomere primordium at the onset of segmentation, which is soon followed by expression in the 5th rhombomere. From mid-segmentation onward, the 5th rhombomere has a higher frb35 expression level than the 3rd rhombomere. Unlike krx20, frb35 expression persists in the 5th rhombomere until the end of pharyngula period.

Amino Acid Sequence↗