Cyclic AMP response element binding protein CREB and its structural homologs CREM and ATF-1 are DNA-binding transcription factors that readily dimerize ...
..) 1992 Oxford University Press
6106 Nucleic Acids Research, 1992, Vol. 20, No. 22
Cyclic AMP response element binding protein CREB and modulator protein CREM are products of distinct genes Terry E.Meyer+ and Joel F.Habener* Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Howard Hughes Medical Institute and Harvard Medical School, Boston, MA 02114, USA Accession nos§
Received August 31, 1992; Accepted September 22, 1992 Cyclic AMP response element binding protein CREB and its structural homologs CREM and ATF- 1 are DNA-binding transcription factors that readily dimerize with one another, bind selectively to cAMP responsive enhancers (CREs), and are activated by phosphorylation mediated via the cAMP-dependent pathway of signal transduction (1). These cAMP-responsive proteins constitute a subfamily of a larger group of bZIP DNAbinding proteins characterized by a basic region and 'leucine zipper' coiled-coil involved in DNA recognition and dimerization, respectively. Because of the remarkably close similarities of the amino acid sequences of CREB [human (2, 3), rat (4)] and CREM [mouse (5)], some uncertainty remains as to whether CREB and CREM are products of separate genes or represent the divergence of a single gene amongst species. Recently, a partial sequence of the mouse CREB gene was reported (6) and comparisons of the mouse CREB and CREM sequences suggest that they are products of distinct genes. Here we report the nucleotide and encoded protein sequences of human and rat CREMS. CREB cDNAs were isolated by polymerase chain reaction amplification of cDNAs synthesized from human placental and rat testis RNAs. Clones of these CREM cDNAs were sequenced by standard dideoxynucleotide methods. Comparison of the sequences among the exons (6) of the CREMs and CREBs establishes unequivocally that the two proteins are derived from different genes (1, and Table). The conservation of both CREB and CREM (all exons) amongst the three animal species is >90% for the nucleotides and 97 % for the amino acid sequences. Between CREB and CREM the highest conservation is in exons E, F, H, and I that encode the two important functional domains, the phosphorylated transactivation region (exons E and F) (7) and the DNA-binding domain (exons H and I) (8). Conservation of these two domains likely reflects the prerequisite for these proteins to be phosphorylated by cAMP-dependant protein kinase A and other kinases to activate the transactivation functions and to bind to specific CREs. Also the overall similarity between CREB and CREM sequences suggests that they arose by gene duplication.
*
To whom correspondence should be addressed
+Present address:
International,
Johnston, §GenBank: M27691; EMBL: Z15158 and Z15159 Pioneer Hi-Bred
IA 50131,
USA
REFERENCES 1. Meyer,T.E. and Habener,J.F. (1991) Cell Activation: Genetic Approaches. In: Mond,J., Weiss,A. and Cambier,J. (eds) Advances in REgulation of Cell Growth. Raven Press, New York Vol. 2, pp. 61-82. 2. Hoeffler,J.P., Meyer,T.E., Yun,Y., Jameson,J.L. and Habener,J.F. (1988)
Science 242, 1430-1433. 3. Hoeffler,J.P., Meyer,T.E., Waeber,G.W., Habener,J.F. (1990) Mol. Endocrinol. 4, 920-930. 4. Gonzalez,G.A., Yamamoto,K.K., Fischer,W.H., Karr,D., Menzel,P., Biggs,W.,III, Vale,W.W. and Montminy,M.R. (1989) Nature 337, 749-752. 5. Foulkes,N.S., Mellstrom,B., Benusiglio,E. and Sasson-Corsi,P. (1992) Nature 355, 80-84. 6. Ruppert,S., Cole,T.J., Boshort,M., Schmidt,E. and Shutz,G. (1992) EMBO J. 11, 1503-1512. 7. Lee,C.Q., Yun,Y., Hoeffler,J.P. and Habener,J.F. (1990) EMBO J. 9, 4455-4465. 8. Yun,Y., Dumoulin,M. and Habener,J.F. (1990) Mol. Endocrinol. 4, 931 -939. 9. Waeber,G., Meyer,T.E., LeSieur,M., Hermann,H.L., Gerard,N. and Habener,J. F. (1991) Mol. Endocninol. 5, 1418 - 1430. Table. Comparisons of nucleic acids and amino acids of rat CREM exons with the structurally related exons of mouse and human CREMs and CREBs.
Exon8 HI B C
E F G
x H l II All
(76)b
T
|
Rat CREB%
94 (97) 99 (98)
42 (55) 67 (82)
41 (57) 63 (82)
41 (54) 63 (82)
71 (84) 66 (83) 74 (78)
69 (84) 69 (78) 72 (78)
69 (84)
(96)
99(100) 100(00) 99(1 00) 100(100) 98(100)
69 (80) 77 (98)
69 (80) 77 (96)
95 (100) 90 (94)
99 (98) 98 (98) 98 (99)
70 (80) 82 (96) 68 (80)
66 (80)
66 (80)
84
|
*mCRu CRE%
f
m
_
93 94
|
(97) (98)
T
T
T 90
|
l
69 (83) 72 (78)
l
'Not all exons are represented inasmuch as the gene structures have only been determined for hCREB (3) and mCREB (6). bPositional identities of nucleotides (similarity of amino acids shown in parentheses).
cAltematively spliced exon. CREB has exons D,Y,W either not present or not yet identified in CREM, and reciprocally, mouse CREB has ; and X not found in human CREB (6, 9), and mouse CREM has X not found in CREB (5).
