[Frontiers in Bioscience E4, 998-1008, January 1, 2012]

The tau-like protein in silkworm (Bombyx mori) induces microtubule bundle formation

Qiao Wang1, Li Chen2, Liang Chen1, Birong Shen1, Yingying Liu1, Jianguo Chen1, Junlin Teng1

1The Key Laboratory of Cell Proliferation and Differentiation of Ministry of Education; The State Key Laboratory of Bio-membrane and Membrane Bio-engineering, College of Life Sciences, Peking University, Beijing 100871, China, 2College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Bombyx mori strain and cell culture
3.2. Bioinformatic analysis
3.3. RNA isolation and cDNA cloning
3.4. Real-time quantitative PCR
3.5. Cell culture, transfection and immunofluorescence
4. Results and Discussion
4.1. cDNA cloning of BmTau
4.2. Bioinformatic characterization of BmTau
4.3. Tissue distribution and developmental expression patterns
4.4. C-terminal MTBDs are essential for subcellular localization
4.5. Microtubule-bundling ability of BmTau
5. Conclusion
6. Acknowledgment
7. References

1. ABSTRACT

Tau proteins are major microtubule-associated proteins (MAPs), which promote polymerization of tubulin and determine spacings between microtubules in axons of both the central and peripheral nervous systems (CNS and PNS). Here, we cloned and identified a tau-like protein BmTau from silkworm, Bombyx mori (GenBank accession number FJ904935). The coding sequence of BmTau is 723 bases long and encodes an approximate 30kDa protein. In the C-terminus of BmTau are contained four predicted microtubule-binding domains, which share strong sequence homology to its ortholog in Drosophila melanoganster. Relative real-time PCR analysis showed ubiquitous expression of BmTau in both neurons and non-neural cells, with its mRNA abundantly expressing in brain but significantly less detected in trachea, fat body, and silkgland. Furthermore, immunocytochemical studies in BmN cells transfected with EGFP-BmTau indicated that BmTau functioned as microtubule bundling protein as its orthologues.