Intron 1 GATA site enhances ALAS2 expression indispensably during erythroid differentiation.

Abstract

The first intronic mutations in the intron 1 GATA site (int-1-GATA) of 5-aminolevulinate synthase 2 (ALAS2) have been identified in X-linked sideroblastic anemia (XLSA) pedigrees, strongly suggesting it could be causal mutations of XLSA. However, the function of this int-1-GATA site during in vivo development remains largely unknown. Here, we generated mice lacking a 13 bp fragment, including this int-1-GATA site (T AGATAA: AGCCCC) and found that hemizygous deletion led to an embryonic lethal phenotype due to severe anemia resulting from a lack of ALAS2 expression, indicating that this non-coding sequence is indispensable for ALAS2 expression in vivo Further analyses revealed that this int-1-GATA site anchored the GATA site in intron 8 (int-8-GATA) and the proximal promoter, forming a long-range loop to enhance ALAS2 expression by an enhancer complex including GATA1, TAL1, LMO2, LDB1 and Pol II at least, in erythroid cells. However, compared with the int-8-GATA site, the int-1-GATA site is more essential for regulating ALAS2 expression through CRISPR/Cas9-mediated site-specific deletion. Therefore, the int-1-GATA site could serve as a valuable site for diagnosing XLSA in cases with unknown mutations.

• Authors: Yingchi Zhang, Jingliao Zhang, Wenbin An, Yang Wan, Shihui Ma, Jie Yin, Xichuan Li, Jie Gao, Weiping Yuan, Ye Guo, James Douglas Engel, Lihong Shi, Tao Cheng, Xiaofan Zhu
• Journal: Nucleic acids research (Nucleic Acids Res) Vol. 45 Issue 2 Pg. 657-671 (01 25 2017) ISSN: 1362-4962 [Electronic] England
• PMID: 28123038 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Chemical References

• GATA1 Transcription Factor
• 5-Aminolevulinate Synthetase
• ALAS2 protein, human

Topics

• 5-Aminolevulinate Synthetase (genetics)
• Anemia, Sideroblastic (genetics)
• Animals
• Base Sequence
• Binding Sites
• CRISPR-Cas Systems
• Cell Differentiation
• Disease Models, Animal
• Enhancer Elements, Genetic
• Erythroid Cells (cytology, metabolism)
• GATA1 Transcription Factor (metabolism)
• Gene Expression Regulation
• Genes, Lethal
• Genetic Diseases, X-Linked (genetics)
• Hematopoietic Stem Cells (cytology, metabolism)
• Hemizygote
• Humans
• Introns
• K562 Cells
• Male
• Mutation
• Pedigree
• Promoter Regions, Genetic
• Sequence Deletion