TABLE 1.
THE MAMMALIAN ATF/CREB FAMILY OF TRANSCRIPTION FACTORS
Subgroup | Members | Spliced Variants | Alternative Names |
---|---|---|---|
CREB* | CREB (42,50) | reviews (44,90,111) | ATF-47† (56) |
CREM (35) | (70), reviews (36,44,111) | ||
ATF1 (49) | ATF1 (49) | TREB36 (140), TCRATF1 (72), ATF-43† (56,57) | |
CRE-BP1* | CRE-BP1 (85) | CRE-BP1 (41,85) | ATF2 (49), HB16 (62), TREB7 (140), TCR-ATF2 (72) |
CRE-BP2 (41) | mXBP‡ (78) | ||
CRE-BP3 (41) | |||
ATFa (40) | ATFa (40) | ATFa2 (14) | |
ATFaΔ (40) | ATFa1 (14) | ||
ATFa3 (14) | |||
ATFa0 (103) | |||
CRE-BPa (101) | CRE-BPα (101,144) | ||
CRE-BPaβ (144) | |||
CRE-BPaγ (144) | |||
CRE-BPaδ (144) | |||
ATF3§ | ATF3 (49) | ATF3 (49) | LRF-1§ (52), LRG-21§ (28), CRG-5§ (31), TI-241§ (58) |
ATF3ΔZip (16) | |||
JDP-2 (5) | |||
ATF4# | ATF4 (49) | ATF4 (49) | CREB2# (64), TAXREB67# (126), mATF4# (91), C/ATF# (130), mTR67# (18) |
ATFx (100) | ATFx (100) | ||
ATF6 | ATF6 (49) | ATF6 (49) | |
CREB-RP (92) | CREB-RP (92) | G13 (66) | |
B-ATF¶ | B-ATF (27) | ||
JDP1 (5) | JDP1 (5) |
The Nomenclature Committee of the Human Genome Project refers to CREB as CREB1 and CRE-BP1 as CREB2. CREB1 is mapped to human chromosome 2q32.3-q34 (124), and CREB2 to human chromosome 2q24.l-q32 (26). Therefore, CREB2 has been used to refer to three proteins: CRE-BP1, ATF4, and an alternatively spliced form of CREB (see text).
The terms, ATF-43 and ATF-47, listed in the table refer to polypeptides: ATF-43 for 43 kDa and ATF-47 for 47 kD. ATF-47 is encoded by CREB (56) and ATF-43 encoded by ATF1 (57).
mxBP (a mouse clone) and hxBP (a human clone) (77) were both identified by their ability to bind to the X box of the MHC promoter. hxBP is not homologous to mxBP, but is identical to TREB5, a bZip protein that does not share significant similarity (except in the bZip motif) to any of the proteins listed in Table 1.
ATF3 (a human clone) and LRF-1 (a rat clone) are over 95% similar at the amino acid level. LRG-21 (also referred to as CRG-5 or TI-241) is a mouse clone highly homologous to ATF3 or LRF-1.
ATF4, CREB2, and TAXREB67 are human clones with the same amino acid sequences. mATF4, C/ATF and mTR67 are mouse clones with virtually identical amino acid sequences, except that mATF4 has extra 31 amino acids at the N′-terminal. The homology between the human and mouse clones is about 85%.
B-ATF (a human clone) shares 60% similarity to ATF3 (also a human clone) in the bZip region. However, it has no significant similarity to ATF3 outside of the bZip region; therefore, we classified it in a different subgroup.
ATF5, not listed in the table, is identical to Fos, a fact not recognized at the time of publication due to sequencing mistakes. Because the cDNA was isolated by screening the expression library withr triplicated ATF/CRE consensus site (49), it indicates that, under some conditions, c-Fos can bind to DNA as a homodimer. This does not contradict the general observation that c-Fos does not bind to DNA as a homodimer; it simply indicates that, at high concentrations of proteins and DNA, a weak interaction can be detected.
ATF7 and ATF8 described in (49) were not sequenced; it is not clear whether they correspond to any other cDNAs.