Molecular Biology Reports

, Volume 35, Issue 2, pp 179–187 | Cite as

A human homolog of mouse Lbh gene, hLBH, expresses in heart and activates SRE and AP-1 mediated MAPK signaling pathway

  • Jianping Ai
  • Yuequn Wang
  • Kunrong Tan
  • Yun Deng
  • Na Luo
  • Wuzhou Yuan
  • Zequn Wang
  • Yongqing Li
  • Ying Wang
  • Xiaoyang Mo
  • Chuanbing Zhu
  • Zhaochu Yin
  • Mingyao Liu
  • Xiushan Wu
Article

Abstract

It has been reported that mouse Lbh (limb-bud and heart) can regulate cardiac gene expression by modulating the combinatorial activities of key cardiac transcription factors, as well as their individual functions in cardiogenesis. Here we report the cloning and characterization of the human homolog of mouse Lbh gene, hLBH, from a human embryonic heart cDNA library. The cDNA of hLBH is 2927 bp long, encoding a protein product of 105 amino acids. The protein is highly conserved in evolution across different species from zebra fish, to mouse, to human. Northern blot analysis indicates that a 2.9 kb transcript specific for hLBH is most abundantly expressed in both embryonic and adult heart tissue. In COS-7 cells, hLBH proteins are localized to both the nucleus and the cytoplasm. hLBH is a transcription activator when fused to Gal-4 DNA-binding domain. Deletion analysis indicates that both the N-terminal containing proline-dependent serine/threonine kinase group and the C-terminal containing ERK D-domain motif are required for transcriptional activation. Overexpression of hLBH in COS-7 cells activates the transcriptional activities of activator protein-1 (AP-1) and serum response element (SRE). These results suggest that hLBH proteins may act as a transcriptional activator in mitogen-activated protein kinase signaling pathway to mediate cellular functions.

Keywords

hLBH Transcription factor Gene regulation SRE AP-1 

Abbreviations

DMEM

Dulbecco’s Modified Eagle Medium

DAPI

4′,6′-diamidino-2-phenylindole hydrochloride

MAPK

Mitogen-activated protein kinase

MAPKK, MKK or MEK

MAPK kinase

MAPKKK or MEKK

A MAPKK kinase or MEK kinase

SRE

Serum response element

AP-1

Activation protein 1

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Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  • Jianping Ai
    • 1
  • Yuequn Wang
    • 1
  • Kunrong Tan
    • 1
  • Yun Deng
    • 1
  • Na Luo
    • 1
  • Wuzhou Yuan
    • 1
  • Zequn Wang
    • 1
  • Yongqing Li
    • 1
  • Ying Wang
    • 1
  • Xiaoyang Mo
    • 1
  • Chuanbing Zhu
    • 1
  • Zhaochu Yin
    • 1
  • Mingyao Liu
    • 1
  • Xiushan Wu
    • 1
  1. 1.The Center For Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life SciencesHunan Normal UniversityChangsha, HunanPeoples’ Republic of China

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