Importance of leucine zipper domain of mitranscription factor (MITF) for differentiation of mast cells demonstrated using mice/mice mutant mice of which MITF lacks the zipper domain

Abstract The mi transcription factor (MITF) is a basic helix-loop-helix leucine zipper (bHLH-Zip) transcription factor that is important for the development of mast cells. Mast cells ofmi/mi genotype express normal amount of abnormal MITF (mi-MITF), whereas mast cells of tg/tg genotype do not express any MITFs. Mast cells of mi/mi mice show more severe abnormalities than those of tg/tg mice, indicating that the mi-MITF possesses the inhibitory function. The MITF encoded by the mice mutant allele (ce-MITF) lacks the Zip domain. We examined the importance of the Zip domain usingmice/micemice. The amounts of c-kit, granzyme B (Gr B), and tryptophan hydroxylase (TPH) messenger RNAs decreased in mast cells ofmice/mice mice to levels comparable to those of tg/tg mice, and the amounts were intermediate between those of +/+ mice and those of mi/mi mice. Gr B mediates the cytotoxic activity of mast cells, and TPH is a rate-limiting enzyme for the synthesis of serotonin. The cytotoxic activity and serotonin content ofmice/mice mast cells were comparable to those of tg/tg mast cells and were significantly higher than those of mi/mi mast cells. The phenotype of mice/mice mast cells was similar to that of tg/tg mast cells rather than to that of mi/mi mast cells, suggesting that thece-MITF had no functions. The Zip domain of MITF appeared to be important for the development of mast cells.

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Systematic Method to Obtain Novel Genes That Are Regulated bymi Transcription Factor: Impaired Expression of Granzyme B and Tryptophan Hydroxylase in mi/mi Cultured Mast Cells

Blood ◽

10.1182/blood.v91.9.3210.3210_3210_3221 ◽

1998 ◽

Vol 91 (9) ◽

pp. 3210-3221 ◽

Cited By ~ 5

Author(s):

Akihiko Ito ◽

Eiichi Morii ◽

Kazutaka Maeyama ◽

Tomoko Jippo ◽

Dae-Ki Kim ◽

...

Keyword(s):

Mast Cells ◽

Leucine Zipper ◽

Tryptophan Hydroxylase ◽

Serotonin Synthesis ◽

Systematic Method ◽

Serotonin Content ◽

Helix Loop Helix ◽

New Genes ◽

Rate Limiting ◽

Leucine Zipper Protein

The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors (hereafter called MITF). We have reported that the expression of several genes was impaired in cultured mast cells (CMCs) ofmi/mi genotype, and demonstrated the involvement of MITF in the transcription of these genes. To obtain new genes whose transcription may be regulated by MITF, we prepared a subtracted cDNA library using +/+ and mi/mi CMCs. We found two clones carrying the granzyme (Gr) B and tryptophan hydroxylase (TPH) cDNAs in the subtracted library. The expression of the Gr B and TPH genes decreased in mi/mi CMCs, and recovered to nearly normal level by the overexpression of normal (+) MITF but not of mutant (mi) MITF. The +-MITF bound three and one CANNTG motifs in the Gr B and TPH promoters, respectively, and transactivated these two genes, indicating the involvement of +-MITF in their expression. Because TPH is the rate-limiting enzyme for serotonin synthesis, we examined the serotonin content of +/+ and mi/mi CMCs. The serotonin content was significantly smaller in mi/mi CMCs than in +/+ CMCs. The introduction of +-MITF but not of mi-MITF normalized the serotonin content in mi/mi CMCs.

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Systematic Method to Obtain Novel Genes That Are Regulated bymi Transcription Factor: Impaired Expression of Granzyme B and Tryptophan Hydroxylase in mi/mi Cultured Mast Cells

Blood ◽

10.1182/blood.v91.9.3210 ◽

1998 ◽

Vol 91 (9) ◽

pp. 3210-3221 ◽

Cited By ~ 53

Author(s):

Akihiko Ito ◽

Eiichi Morii ◽

Kazutaka Maeyama ◽

Tomoko Jippo ◽

Dae-Ki Kim ◽

...

Keyword(s):

Mast Cells ◽

Leucine Zipper ◽

Tryptophan Hydroxylase ◽

Serotonin Synthesis ◽

Systematic Method ◽

Serotonin Content ◽

Helix Loop Helix ◽

New Genes ◽

Rate Limiting ◽

Leucine Zipper Protein

Abstract The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors (hereafter called MITF). We have reported that the expression of several genes was impaired in cultured mast cells (CMCs) ofmi/mi genotype, and demonstrated the involvement of MITF in the transcription of these genes. To obtain new genes whose transcription may be regulated by MITF, we prepared a subtracted cDNA library using +/+ and mi/mi CMCs. We found two clones carrying the granzyme (Gr) B and tryptophan hydroxylase (TPH) cDNAs in the subtracted library. The expression of the Gr B and TPH genes decreased in mi/mi CMCs, and recovered to nearly normal level by the overexpression of normal (+) MITF but not of mutant (mi) MITF. The +-MITF bound three and one CANNTG motifs in the Gr B and TPH promoters, respectively, and transactivated these two genes, indicating the involvement of +-MITF in their expression. Because TPH is the rate-limiting enzyme for serotonin synthesis, we examined the serotonin content of +/+ and mi/mi CMCs. The serotonin content was significantly smaller in mi/mi CMCs than in +/+ CMCs. The introduction of +-MITF but not of mi-MITF normalized the serotonin content in mi/mi CMCs.

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Inhibitory Effect of the Transcription Factor Encoded by themi Mutant Allele in Cultured Mast Cells of Mice

Blood ◽

10.1182/blood.v93.4.1189.404k32_1189_1196 ◽

1999 ◽

Vol 93 (4) ◽

pp. 1189-1196 ◽

Cited By ~ 2

Author(s):

Akihiko Ito ◽

Eiichi Morii ◽

Dae-Ki Kim ◽

Tatsuki R. Kataoka ◽

Tomoko Jippo ◽

...

Keyword(s):

Transcription Factor ◽

Mast Cells ◽

Leucine Zipper ◽

Tryptophan Hydroxylase ◽

Cdna Probe ◽

Inhibitory Effect ◽

Northern Analysis ◽

Helix Loop Helix ◽

Genes Encoding ◽

Mouse Mast Cell

The mi locus of mice encodes a transcription factor of the basic-helix-loop-helix-leucine zipper protein family (MITF). The MITF encoded by the mutant mi allele (mi-MITF) deletes 1 of 4 consecutive arginines in the basic domain. The mice of mi/migenotype express mi-MITF, whereas the mice of tg/tggenotype have a transgene at the 5′ flanking region of themi gene and do not express any MITF. To investigate the function of mi-MITF in cultured mast cells (CMCs), we took two approaches. First, mRNA obtained from mi/mi CMCs ortg/tg CMCs was subtracted from complementary (c) DNA library of normal (+/+) CMCs, and the (+/+-mi/mi) and (+/+-tg/tg) subtraction libraries were obtained. When the number of clones that hybridized more efficiently with +/+ CMC cDNA probe than with mi/mi or tg/tg CMC cDNA probe was compared using Southern analysis, the number was larger in the (+/+-mi/mi) library than in the (+/+-tg/tg) library. Second, we compared mRNA expression of six genes betweenmi/mi and tg/tg CMCs by Northern analysis. The transcription of three genes encoding mouse mast cell proteases was impaired in both mi/mi and tg/tg CMCs. On the other hand, the transcription of three genes encoding c-kit receptor, tryptophan hydroxylase, and granzyme B was markedly reduced inmi/mi CMCs, but the reduction was significantly smaller intg/tg CMCs. These results indicated the inhibitory effect ofmi-MITF on the transactivation of particular genes in CMCs.

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Effect of a large deletion of the basic domain of mitranscription factor on differentiation of mast cells

Blood ◽

10.1182/blood.v98.8.2577 ◽

2001 ◽

Vol 98 (8) ◽

pp. 2577-2579 ◽

Cited By ~ 16

Author(s):

Eiichi Morii ◽

Hideki Ogihara ◽

Keisuke Oboki ◽

Tatsuki R. Kataoka ◽

Kazutaka Maeyama ◽

...

Keyword(s):

Transcription Factor ◽

Mast Cells ◽

Leucine Zipper ◽

Large Deletion ◽

Single Amino Acid ◽

Amino Acid Deletion ◽

Basic Domain ◽

Basic Helix Loop Helix ◽

Helix Loop Helix ◽

Inhibitory Function

Abstract The mi transcription factor (MITF) is a basic-helix-loop-helix-leucine zipper transcription factor that is important for the development of mast cells. Cultured mast cells (CMCs) of mi/mi genotype express abnormal MITF (mi-MITF), but CMCs of tg/tg genotype do not express any MITFs. It was previously reported thatmi/mi CMCs showed more severe abnormalities thantg/tg CMCs, indicating that mi-MITF had inhibitory function. Whereas mi-MITF contains a single amino acid deletion in the basic domain, MITF encoded bymiewallele (ew-MITF) deletes 16 of 21 amino acids of the basic domain. Here the effect of a large deletion of the basic domain was examined. Inmiew/miew CMCs, the expression pattern of genes whose transcription was affected by MITF was comparable to that of tg/tg CMCs rather than to that ofmi/mi CMCs. This suggested that ew-MITF lacked any functions. The part of the basic domain deleted inew-MITF appeared necessary for either transactivation or inhibition of transactivation.

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Inhibitory Effect of the Transcription Factor Encoded by themi Mutant Allele in Cultured Mast Cells of Mice

Blood ◽

10.1182/blood.v93.4.1189 ◽

1999 ◽

Vol 93 (4) ◽

pp. 1189-1196 ◽

Cited By ~ 38

Author(s):

Akihiko Ito ◽

Eiichi Morii ◽

Dae-Ki Kim ◽

Tatsuki R. Kataoka ◽

Tomoko Jippo ◽

...

Keyword(s):

Transcription Factor ◽

Mast Cells ◽

Leucine Zipper ◽

Tryptophan Hydroxylase ◽

Cdna Probe ◽

Inhibitory Effect ◽

Northern Analysis ◽

Helix Loop Helix ◽

Genes Encoding ◽

Mouse Mast Cell

Abstract The mi locus of mice encodes a transcription factor of the basic-helix-loop-helix-leucine zipper protein family (MITF). The MITF encoded by the mutant mi allele (mi-MITF) deletes 1 of 4 consecutive arginines in the basic domain. The mice of mi/migenotype express mi-MITF, whereas the mice of tg/tggenotype have a transgene at the 5′ flanking region of themi gene and do not express any MITF. To investigate the function of mi-MITF in cultured mast cells (CMCs), we took two approaches. First, mRNA obtained from mi/mi CMCs ortg/tg CMCs was subtracted from complementary (c) DNA library of normal (+/+) CMCs, and the (+/+-mi/mi) and (+/+-tg/tg) subtraction libraries were obtained. When the number of clones that hybridized more efficiently with +/+ CMC cDNA probe than with mi/mi or tg/tg CMC cDNA probe was compared using Southern analysis, the number was larger in the (+/+-mi/mi) library than in the (+/+-tg/tg) library. Second, we compared mRNA expression of six genes betweenmi/mi and tg/tg CMCs by Northern analysis. The transcription of three genes encoding mouse mast cell proteases was impaired in both mi/mi and tg/tg CMCs. On the other hand, the transcription of three genes encoding c-kit receptor, tryptophan hydroxylase, and granzyme B was markedly reduced inmi/mi CMCs, but the reduction was significantly smaller intg/tg CMCs. These results indicated the inhibitory effect ofmi-MITF on the transactivation of particular genes in CMCs.

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Additive effect of mouse genetic background and mutation ofMITF gene on decrease of skin mast cells

Blood ◽

10.1182/blood-2002-07-2213 ◽

2003 ◽

Vol 101 (4) ◽

pp. 1344-1350 ◽

Cited By ~ 7

Author(s):

Eiichi Morii ◽

Keisuke Oboki ◽

Tomoko Jippo ◽

Yukihiko Kitamura

Keyword(s):

Transcription Factor ◽

Mast Cells ◽

Receptor Tyrosine Kinase ◽

Genetic Background ◽

Leucine Zipper ◽

Basic Helix Loop Helix ◽

Kit Ligand ◽

Helix Loop Helix ◽

Kit Receptor ◽

Mouse Genetic

The mi transcription factor (MITF) is a basic-helix-loop-helix leucine zipper transcription factor and is encoded by mi locus. The mi/mi mutant mice showed a significant decrease of skin mast cells in C57BL/6 (B6) genetic background but not in WB genetic background. Kit ligand (KitL) is the most important growth factor for development of mast cells, and the decrease of skin mast cells in B6-mi/mi mice was attributable to the reduced expression of c-kit receptor tyrosine kinase (KIT) that is a receptor for KitL. However, the expression level of KIT in WB-mi/mi mast cells was comparable with that of B6-mi/mi mast cells, suggesting that a factor compensating the reduced expression of KIT was present in WB-mi/mi mice. By linkage analysis, such a factor was mapped on chromosome 10. The mapped position was closely located to the KitL locus. Two alternative spliced forms are known in KitL mRNA: KL-1 and KL-2. Soluble KitL, which is important for development of skin mast cells, is produced more efficiently from KL-1 mRNA than from KL-2 mRNA. The KL-1/KL-2 ratio was higher in WB-mi/mi than in B6-mi/mi mice, suggesting that the larger amount of soluble KitL may compensate for the reduced expression of KIT in WB-mi/mi mice.

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Identification and function of phosphorylation in the glucose-regulated transcription factor ChREBP

Biochemical Journal ◽

10.1042/bj20071156 ◽

2008 ◽

Vol 411 (2) ◽

pp. 261-270 ◽

Cited By ~ 28

Author(s):

Nikolas G. Tsatsos ◽

Michael N. Davies ◽

Brennon L. O'callaghan ◽

Howard C. Towle

Keyword(s):

Transcription Factor ◽

High Glucose ◽

Leucine Zipper ◽

De Novo ◽

Regulatory Region ◽

De Novo Lipogenesis ◽

Nuclear Accumulation ◽

Helix Loop Helix ◽

Genes Encoding ◽

And Function

In the liver, induction of genes encoding enzymes involved in de novo lipogenesis occurs in response to increased glucose metabolism. ChREBP (carbohydrate-response-element-binding protein) is a basic helix–loop–helix/leucine zipper transcription factor that regulates expression of these genes. To evaluate the potential role of ChREBP phosphorylation in its regulation, we used MS to identify modified residues. In the present paper, we report the detection of multiple phosphorylation sites of ChREBP expressed in hepatocytes, several of which are only observed under high-glucose conditions. Mutation of each of these serine/threonine residues of ChREBP did not alter its ability to respond to glucose. However, mutation of five N-terminal phosphoacceptor sites resulted in a major decrease in activity under high-glucose conditions. These phosphorylated residues are located within a region of ChREBP (amino acids 1–197) that is critical for glucose regulation. Mutation of Ser56 within this region to an aspartate residue resulted in increased nuclear accumulation and activity under high-glucose conditions. Together, these data suggest that ChREBP activity is regulated by complex multisite phosphorylation patterns involving its N-terminal regulatory region.

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Impaired Expression of Integrin -4 Subunit in Cultured Mast Cells Derived From Mutant Mice of mi/mi Genotype

Blood ◽

10.1182/blood.v92.6.1973 ◽

1998 ◽

Vol 92 (6) ◽

pp. 1973-1980 ◽

Cited By ~ 22

Author(s):

Dae-Ki Kim ◽

Eiichi Morii ◽

Hideki Ogihara ◽

Koji Hashimoto ◽

Kenji Oritani ◽

...

Keyword(s):

Mast Cells ◽

Cell Adhesion Molecule ◽

Leucine Zipper ◽

Subunit Gene ◽

Vascular Cell Adhesion ◽

Gene Encoding ◽

Helix Loop Helix ◽

American Society ◽

Cell Adhesion Molecule 1 ◽

Leucine Zipper Protein

Abstract The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors (hereafter called MITF). We have reported that expression of several genes was impaired in cultured mast cells (CMCs) ofmi/mi mice due to a defective transactivation ability of mutant MITF (mi-MITF). Because attachment of mi/mi CMCs to fibroblasts is impaired, we examined the expression of integrin genes in mi/mi CMCs in the present study. Among the integrin genes examined, the expression of integrin 4 subunit was barely detectable in mi/mi CMCs, and the 4 protein was not detected by flow cytometry either. The specific adhesion to vascular cell adhesion molecule-1 (VCAM-1), the ligand for 4 subunit, was observed in +/+ CMCs but not in mi/mi CMCs, indicating that the expression of integrin 4 subunit at a functional level did not occur in mi/mi CMCs. In the promoter region of the 4 subunit gene, there was a CACTTG motif to which normal MITF (+- MITF) bound. The coexpression of +-MITF but not of mi-MITF transactivated the promoter of the 4 subunit gene. The deletion or mutation of the CACTTG motif abolished the transactivation by +-MITF, suggesting that +-MITF directly transactivated the gene encoding 4 subunit of integrin. © 1998 by The American Society of Hematology.

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