Key points are not available for this paper at this time.
Bicarbonate/chloride (HCO−3/Cl−) exchangers regulate intracellular pH in the alkaline range. Previously, it has been shown that mouse embryos at the two-cell stage exhibit this activity, but that the otherwise ubiquitous mechanisms for regulating intracellular pH in the acid-to-neutral range are undetectable. We have examined mouse embryos during preimplantation development (one-cell zygote through blastocyst) to determine whether HCO−3;/Cl− exchange activity exists at all stages, whether it is necessary for preimplantation development, and whether messenger RNAs from the known HCO−3;/Cl− exchanger genes are expressed. We have found that all stages of preimplantation embryo have detectable HCO−3;/Cl− exchange activity. In addition, inhibition of this activity with the stilbene anion exchange inhibitor DIDS (4,4′-diisothiocyanostilbene-2,2′-disulfonic acid) disrupts intracellular pH homeostasis and markedly inhibits embryo development from the two-cell stage to blastocysts in culture under conditions of moderately high external pH. Finally, mRNA encoding two members of the band 3-related AE anion exchanger gene family are expressed in preimplantation embryos. Bicarbonate/chloride (HCO−3/Cl−) exchangers regulate intracellular pH in the alkaline range. Previously, it has been shown that mouse embryos at the two-cell stage exhibit this activity, but that the otherwise ubiquitous mechanisms for regulating intracellular pH in the acid-to-neutral range are undetectable. We have examined mouse embryos during preimplantation development (one-cell zygote through blastocyst) to determine whether HCO−3;/Cl− exchange activity exists at all stages, whether it is necessary for preimplantation development, and whether messenger RNAs from the known HCO−3;/Cl− exchanger genes are expressed. We have found that all stages of preimplantation embryo have detectable HCO−3;/Cl− exchange activity. In addition, inhibition of this activity with the stilbene anion exchange inhibitor DIDS (4,4′-diisothiocyanostilbene-2,2′-disulfonic acid) disrupts intracellular pH homeostasis and markedly inhibits embryo development from the two-cell stage to blastocysts in culture under conditions of moderately high external pH. Finally, mRNA encoding two members of the band 3-related AE anion exchanger gene family are expressed in preimplantation embryos. INTRODUCTIONThe two-cell stage mouse embryo has been shown to exhibit HCO−3;/Cl− exchange activity which mediates recovery from intracellular alkalosis(1Baltz J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 17212-17217Abstract Full Text PDF PubMed Google Scholar). Biochemically, this activity is much like HCO−3;/Cl− exchange activities found in many cultured mammalian cells: it is inhibitable by the stilbene drug DIDS, 1The abbreviations used are: DIDS4,4′-diisothiocyanostilbene-2,2′-disulfonic acidSNARF-1carboxyseminapthorhodafluor-1SNARF-1-AMacetoxymethylester derivative of SNARF-1PMSGpregnant mare serum gonadotropinhCGhuman chorionic gonadotropinANOVAanalysis of variancePCRpolymerase chain reactionRTreverse transcribed. is active above about pH 7.2 and has a Km for external Cl− in the millimolar range(1Baltz J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 17212-17217Abstract Full Text PDF PubMed Google Scholar). Surprisingly, there was no detectable corresponding activity of mechanisms to correct deviations of pHi in the acid direction, such as the otherwise ubiquitous Na+/H+ antiporter (2Baltz J.M. Biggers J.D. Lechene C. Dev. Biol. 1990; 138: 421-429Crossref PubMed Scopus (56) Google Scholar) or the Na+,HCO−3;/Cl− exchanger(3Baltz J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 6052-6057Abstract Full Text PDF PubMed Google Scholar). Similarly, the unfertilized mouse egg has been reported to lack Na+/H+ antiport activity(4House C.R. Zygote. 1994; 2: 37-45Crossref PubMed Scopus (18) Google Scholar). Thus, HCO−3;/Cl− exchange appears to be the sole pHi regulatory mechanism in the early embryo (at least at the two-cell stage).Three genes encoding HCO−3;/Cl− exchangers have been identified in mammals(5Alper S.L. Cell Physiol. Biochem. 1994; 4: 265-281Crossref Scopus (91) Google Scholar). All are related and are homologs of the erythroid anion exchanger, band 3, which functions as both a HCO−3;/Cl− exchanger and a membrane anchor of the cytoskeleton in erythrocytes. These homologs are designated AE1, AE2, and AE3 (“AE” for “anion exchanger”). The AE1 gene encodes at least two alternate polypeptides, erythroid band 3(6Kopito R.R. Lodish H.F. Nature. 1985; 316: 234-238Crossref PubMed Scopus (381) Google Scholar), and an N terminally truncated kidney-specific form (7Kudrycki K.E. Shull G.E. J. Biol. Chem. 1989; 264: 8185-8192Abstract Full Text PDF PubMed Google Scholar, 8Brosius F.C. Alper S.L. Garcia A.M. Lodish H.F. J. Biol. Chem. 1989; 264: 7784-7787Abstract Full Text PDF PubMed Google Scholar) apparently active in renal acid secretion (9Alper S.L. Natale J. Gluck S. Lodish H.F. Brown D. Proc. Nat. Acad. Sci. (U. S. A.). 1989; 86: 5429-5433Crossref PubMed Scopus (332) Google Scholar). The AE2 gene encodes at least one polypeptide, which is widely distributed among various tissues and cultured cell lines(10Alper S.L. Kopito R.R. Libresco S.M. Lodish H.F. J. Biol. Chem. 1988; 263: 17092-17099Abstract Full Text PDF PubMed Google Scholar, 11Kudrycki K.E. Newman P.R. Shull G.E. J. Biol. Chem. 1990; 265: 462-471Abstract Full Text PDF PubMed Google Scholar) where it may mediate pHi regulation(12Jiang L. Stuart-Tilley A. Parkash J. Alper S.L. Am. J. Physiol. 1994; 267: C845-C856Crossref PubMed Google Scholar, 13Humphreys B.D. Jiang L. Chernova M.N. Alper S.L. Am. J. Physiol. 1994; 267: C1295-C1307Crossref PubMed Google Scholar), and/or volume regulation(14Humphreys B.D. Jiang L. Chernova M.N. Alper S.L. Am. J. Physiol. Cell Physiol. 1995; 37: C201-C209Crossref Google Scholar). The AE3 gene encodes at least two alternate transmembrane polypeptides with differing N termini. One was first cloned from brain and is termed the “brain” isoform(11Kudrycki K.E. Newman P.R. Shull G.E. J. Biol. Chem. 1990; 265: 462-471Abstract Full Text PDF PubMed Google Scholar, 15Kopito R.R. Lee B.S. Simmons D.M. Lindsey A.E. Morgans C.W. Schneider K. Cell. 1989; 59: 927-937Abstract Full Text PDF PubMed Scopus (204) Google Scholar, 16Yannoukakos D. Stuart-Tilley A. Fernandez H.A. Alper S.L. 1994; PubMed Scopus Google Scholar), the was cloned from and is termed the D. Stuart-Tilley A. Fernandez H.A. Alper S.L. 1994; PubMed Scopus Google Scholar, K.E. Shull G.E. J. Biol. Chem. 267: Full Text PDF PubMed Google Scholar). In addition, mRNA encoding a the transmembrane has been C.W. Kopito R.R. J. Cell Sci. Google Scholar). is known all HCO−3;/Cl− exchangers are members of the AE or this the of HCO−3;/Cl− exchange in all cell where it has been examined of the of the AE by HCO−3;/Cl− exchange has in various cell and by expressed AE HCO−3;/Cl− exchange is above a pHi which is J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 17212-17217Abstract Full Text PDF PubMed Google Scholar, Brown J. Biol. Chem. 1988; 263: Full Text PDF PubMed Google Scholar, B.S. Kopito R.R. J. Biol. Chem. 1991; 266: Full Text PDF PubMed Google Scholar, K. J. Biol. Chem. Full Text PDF PubMed Google Scholar, S. K. J. Cell Biol. PubMed Scopus Google Scholar). be by of the L. Stuart-Tilley A. Parkash J. Alper S.L. Am. J. Physiol. 1994; 267: C845-C856Crossref PubMed Google Scholar, S. K. J. Cell Biol. PubMed Scopus Google Scholar). The activity is by stilbene such as DIDS, in the and an Cl− and Cl− for the and the Km for both is in the range of HCO−3;/Cl− exchange activity has been in the two-cell mouse the of this HCO−3;/Cl− a for HCO−3;/Cl− exchange activity in early development has been In addition, there has been no the or of HCO−3;/Cl− exchange activity in stages of preimplantation The from of by with stage two-cell stage and blastocysts and and two-cell stage embryos by with by and blastocysts by or The embryos and in the embryo culture Biggers J.D. Scopus Google Scholar) as and serum from embryo culture or culture The pH of as a of was with a pH with and pH the with a a with The pH of at and is and Biggers J.D. Scopus Google Scholar), of the in is by with to at was used for and the in with and the stage embryos culture at cultured in of in the Scholar) under in culture in a at and the anion exchange inhibitor DIDS by in to the of DIDS the the found that of the DIDS by at with a of of two-cell embryos culture with the DIDS and and to the all embryos in the stage by embryos to be blastocysts a and a cell cultured in this at and of expressed as the of embryos the stage of or at for where there These for and found to be by for one at which was The for The by which of the of as as The by this for and with and pH of embryo pHi an by with a a was a with an The was with a with a and a All are by and and a The pHi a embryos in for at was of and in from embryos at various pHi that was an was The of at by that at was a the and the for embryo or cell two-cell The was related to pH in the range of to pH by pHi to the and in J.M. Biggers J.D. Lechene C. Dev. Biol. 1990; 138: 421-429Crossref PubMed Scopus (56) Google Scholar, PubMed Scopus Google of under the of DIDS the pHi of cultured pHi of two-cell stage embryos was under conditions that as to culture conditions as embryos in culture or DIDS, as for and the with an of or in of and of the embryos in and two from the embryos and the of embryo cell to embryos at with and DIDS The from conditions and by determine there was a of the by two one the with at all and the the with at all These determine pHi in or in determine DIDS a the by an The as two and by it as a pHi the or of DIDS of HCO−3;/Cl− in exchanger be by pHi during of the external with one which J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 6052-6057Abstract Full Text PDF PubMed Google Scholar, Brown J. Biol. Chem. 1988; 263: Full Text PDF PubMed Google Scholar, D. J. Biol. Chem. 1988; 263: Full Text PDF PubMed Google Scholar). The of Cl− through HCO−3;/Cl− an of the The exchanger in the to that by but HCO−3;/Cl− is by that the is by DIDS but of external embryos a and and with a in pHi for the with by was by that was that Cl− was by and DIDS was used to and and was used to and by of Cl− by and by at the and stages by through a to DIDS to the J.M. Biggers J.D. Lechene C. Google Scholar). with and DIDS, and two at stage The expressed as the pHi of the of embryos at by the of pHi Cl− and by the in of pHi was by a the of the the first (one-cell or at The was as the the pHi to Cl− and the or pHi Cl− was to determine whether the of and/or in the or of this was by at The to determine the of or in pHi that there was no in the and two-cell stages, the and stages, the for and two-cell and for and for determine there was a development, to and the and and the and of mRNA and of from the embryos as and through The embryos in a with for at which which otherwise from the is it was active in this as of embryos of in with of The and the with a and in with The mRNA from the embryos was in volume the and of mRNA in from anion exchanger in of as In addition, for and in the of mRNA by a a was used in which the of the and a of was the and a to the first to the of the of for AE1, AE2, and AE3 and The of the mouse anion exchanger used for AE1, R.R. Lodish H.F. Nature. 1985; 316: 234-238Crossref PubMed Scopus (381) Google for AE2, and for The to AE1 AE1 AE1 AE2 AE2 AE2 AE3 AE3 AE3 with was used with of embryo to or in The was and or at by a The and with The from for the AE1, AE2, for the AE1, AE2, at least one in that to be that from and embryo in which was all Thus, from for the that was and was used from tissues known to of a AE was in with a AE1, was used as a and as K.E. Newman P.R. Shull G.E. J. Biol. Chem. 1990; 265: 462-471Abstract Full Text PDF PubMed Google for was used as and as K.E. Newman P.R. Shull G.E. J. Biol. Chem. 1990; 265: 462-471Abstract Full Text PDF PubMed Google Scholar). there is no which has been shown to be for AE2, and no S.L. Kopito R.R. Libresco S.M. Lodish H.F. J. Biol. Chem. 1988; 263: 17092-17099Abstract Full Text PDF PubMed Google Scholar, 11Kudrycki K.E. Newman P.R. Shull G.E. J. Biol. Chem. 1990; 265: 462-471Abstract Full Text PDF PubMed Google and all of the tissues detectable band of the all Thus, by are to from and of of of by The AE1 of and the AE2 of and the AE3 of and for as that the the and was for and was at a The and in the as by the and to the and for and with the which as as of was with which which a to of and and of the with the of and The and both of in a of pH and the DIDS in stage mouse embryos cultured for at and or the of two-cell embryos which the stage by in culture as a of and pH. as as a the of embryos to the stage by of the of where are a was by the and the Thus, two-cell stage embryos at a high to the stage in with high of the anion exchange DIDS in the culture with no the of embryos to blastocysts by in of the embryos to blastocysts in the of DIDS, which is from the in the of DIDS by Thus, DIDS is at to DIDS the development of with the stage at and as to the in the of DIDS that the of DIDS was and that it an with the was by The DIDS and an and DIDS of a was by the and was in which a been to an by the and to that to the that both the of DIDS and the DIDS and and from DIDS, but in with pH of under the inhibition of development which external and DIDS are was to an in intracellular pHi of two-cell stage embryos was under the conditions in which cultured with or DIDS, in or was to for a of under the of in the of DIDS a the in the of DIDS, the at and a much to pHi by the at in embryos the of pHi and the pHi shown the of The pHi at and and in the of DIDS and and in the of of embryo pHi are by the in pH of two-cell embryos in culture as a of with and the HCO−3;/Cl− exchange inhibitor the intracellular the and intracellular pH was under the conditions in which embryos The of the HCO−3;/Cl− exchange inhibitor DIDS in to The was much at The the and the pHi The the pHi from to the at the of the the is the the and of the are the and and the the and for and of was in two the of at was by the and it was found that a pHi the was in the of DIDS, and at but at or The the of the of DIDS and was the this the be to be by and the of by it a and the for was The of DIDS was found to be with Thus, the of DIDS in culture pHi all in at of the in pHi at Thus, pHi is by DIDS in the is much at with pHi high at and in the of DIDS of HCO−3;/Cl− at exchange was by the with and there was an in pHi under and the of at the and to in a in pHi at a or and in The of the is but may be to of acid or the J.M. Biggers J.D. Lechene C. Google Scholar). The was by the anion exchange inhibitor DIDS The of in the of DIDS are all with DIDS at the by and for and The pHi in the of DIDS are all with DIDS at the by and for and exchanger activity during preimplantation of pHi in and stage embryos and to pHi was in the in embryos in Cl− and the was by which an in pHi at The was by lack of external of but was by DIDS of the pHi in a of embryos in one are by the of where are by of pHi at The of of pHi of the with was by in the The the of this at the in with the in the of external the the in the of for in The in pHi from to in is shown for stage the in with the in the of external the the in the of for in pHi Cl− be by HCO−3;/Cl− exchange or Na+,HCO−3;/Cl− that HCO−3;/Cl− Cl− was in In the of external pHi of Cl− at The of from the at stage and by The of the from at stage and there was no of Na+,HCO−3;/Cl− exchange activity at stage that the in pHi Cl− at stage that there is HCO−3;/Cl− exchange activity at determine whether there was a in the of of or in in the of preimplantation development, a was to for a the for and two-cell stages, and the for and blastocysts and and and stage that there was no in and the of and the from the and two-cell stages to the and stages for and for in at the and stages examined by for the of for of the known HCO−3;/Cl− exchanger AE1, AE2, and the of of AE2 is detectable at the and stages, at the and at the two-cell stage AE1 AE3 is at stage the both AE2 and AE3 detectable during preimplantation AE2 was found the preimplantation with the of at the and stages, with the with AE3 was from the two-cell stage through the but was in a of of stage embryos In AE1 and in a of at the and stages, and at the two-cell or stages of corresponding to AE found in of the which the embryos for known HCO−3;/Cl− exchanger mRNA in preimplantation embryos. The are as two-cell all stages are shown for of AE1, AE2, and as of are at of The at and are shown at AE2 are at the and stages, at the and are at the two-cell The first two of are of of tissues known to the mRNA are as in A. The are from with from the of are of a of the in which the embryos to the embryo of are at of The at and are as in that the from AE used to the and that the of the the from embryos all the and from the designated AE of of HCO−3;/Cl− exchanger of to used to the shown in that of and the was used for and The with and the of the from the The AE is at the stages are at the as and for and The and of is under the at and are shown at HCO−3;/Cl− that HCO−3;/Cl− exchange activity preimplantation embryo development in the We have the of HCO−3;/Cl− exchange activity at stage by a pHi of Cl− from the external which Cl− from the cell and through HCO−3;/Cl− exchanger this pHi is to HCO−3;/Cl− exchange is by the of the by DIDS, and lack of external HCO−3;/Cl− exchange activity, by this is at the and two-cell stages and by the and In addition, in in and J. that recovery from an intracellular is external Cl− and at stage of preimplantation the of HCO−3;/Cl− exchange preimplantation HCO−3;/Cl− for culture conditions pH inhibition of HCO−3;/Cl− exchange activity by the anion exchange inhibitor DIDS the of two-cell embryos which the stage by of culture that DIDS (at is to embryos. DIDS pHi under conditions the external pH during culture is by the of DIDS has a embryo of two-cell embryos to blastocysts in the pH used (at and but this to DIDS and high pH are embryos are to moderately alkaline HCO−3;/Cl− exchange is necessary for at pH of two-cell embryos to but this to in the of Thus, it appears that HCO−3;/Cl− exchange activity is necessary for embryo development in the of in external pH. it has been shown that HCO−3;/Cl− exchange activity in pHi and volume in many cell this is the first that HCO−3;/Cl− exchange activity is for or development in or in pHi is the of the development in HCO−3;/Cl− exchange activity is DIDS, the pHi is 7.2 the external pH is above in is of activity of the embryo HCO−3;/Cl− exchanger, is about J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 17212-17217Abstract Full Text PDF PubMed Google Scholar). in the of DIDS, pHi is at all the exchanger pHi to above with the pHi in embryos to above at the The pHi with the embryo as be from the shown in the that the of pHi is about the of embryos in which to is to the pHi are above a embryos with pHi and which to has been of culture at with DIDS under culture HCO−3;/Cl− exchange activity is for development in it is to be necessary for development in The pH of and have been in the but in where this has been the embryos has been found to have a high and high with to pH in the L. Full Text PDF PubMed Google Scholar), and in the and Thus, culture conditions may embryos to in the of HCO−3;/Cl− exchange activity, it may be in at least in the of preimplantation development that in the is from that pHi is at this may a the embryos which in the of by AE HCO−3;/Cl− in that AE are expressed in preimplantation mouse embryos. AE2 is apparently expressed preimplantation is detectable mRNA from the of as as of and a AE3 appears to be expressed at least from the two-cell stage as it is detectable with In a AE3 was that this is of the was and was in a of the embryo AE1 mRNA is expressed at a in the preimplantation a in a of at the and is an In in which a of an mRNA are These be by for the AE2 and AE3 which are expressed at have shown that the which used of AE mRNA in tissues known to of an AE and the are from from AE2 is of from the of as as (one-cell and AE3 is from as as AE mRNA was at embryo stage as be for be from both the and it is and the two-cell where the from to gene in the AE3 to be a of the appears that preimplantation stage mouse embryos mRNA for at least two members of the AE HCO−3;/Cl− exchanger family AE2 and the polypeptides by the AE2 and AE3 genes for the pHi regulatory HCO−3;/Cl− exchange activity which have in the preimplantation is of two anion AE2 is the to be for HCO−3;/Cl− exchange activity at the there is HCO−3;/Cl− exchange activity at the stage but or no AE3 detectable at this in there is a AE2 it be shown which AE are in the of embryos and that are for the HCO−3;/Cl− exchange activity and pHi have shown that preimplantation mouse embryos the for at least two HCO−3;/Cl− AE2 and One or both of may mediate the HCO−3;/Cl− exchange activity shown to regulate pHi at the two-cell stage and shown to preimplantation activity is necessary for embryo and in conditions where the external is moderately as may in the embryo development HCO−3;/Cl− INTRODUCTIONThe two-cell stage mouse embryo has been shown to exhibit HCO−3;/Cl− exchange activity which mediates recovery from intracellular alkalosis(1Baltz J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 17212-17217Abstract Full Text PDF PubMed Google Scholar). Biochemically, this activity is much like HCO−3;/Cl− exchange activities found in many cultured mammalian cells: it is inhibitable by the stilbene drug DIDS, 1The abbreviations used are: DIDS4,4′-diisothiocyanostilbene-2,2′-disulfonic acidSNARF-1carboxyseminapthorhodafluor-1SNARF-1-AMacetoxymethylester derivative of SNARF-1PMSGpregnant mare serum gonadotropinhCGhuman chorionic gonadotropinANOVAanalysis of variancePCRpolymerase chain reactionRTreverse transcribed. is active above about pH 7.2 and has a Km for external Cl− in the millimolar range(1Baltz J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 17212-17217Abstract Full Text PDF PubMed Google Scholar). Surprisingly, there was no detectable corresponding activity of mechanisms to correct deviations of pHi in the acid direction, such as the otherwise ubiquitous Na+/H+ antiporter (2Baltz J.M. Biggers J.D. Lechene C. Dev. Biol. 1990; 138: 421-429Crossref PubMed Scopus (56) Google Scholar) or the Na+,HCO−3;/Cl− exchanger(3Baltz J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 6052-6057Abstract Full Text PDF PubMed Google Scholar). Similarly, the unfertilized mouse egg has been reported to lack Na+/H+ antiport activity(4House C.R. Zygote. 1994; 2: 37-45Crossref PubMed Scopus (18) Google Scholar). Thus, HCO−3;/Cl− exchange appears to be the sole pHi regulatory mechanism in the early embryo (at least at the two-cell stage).Three genes encoding HCO−3;/Cl− exchangers have been identified in mammals(5Alper S.L. Cell Physiol. Biochem. 1994; 4: 265-281Crossref Scopus (91) Google Scholar). All are related and are homologs of the erythroid anion exchanger, band 3, which functions as both a HCO−3;/Cl− exchanger and a membrane anchor of the cytoskeleton in erythrocytes. These homologs are designated AE1, AE2, and AE3 (“AE” for “anion exchanger”). The AE1 gene encodes at least two alternate polypeptides, erythroid band 3(6Kopito R.R. Lodish H.F. Nature. 1985; 316: 234-238Crossref PubMed Scopus (381) Google Scholar), and an N terminally truncated kidney-specific form (7Kudrycki K.E. Shull G.E. J. Biol. Chem. 1989; 264: 8185-8192Abstract Full Text PDF PubMed Google Scholar, 8Brosius F.C. Alper S.L. Garcia A.M. Lodish H.F. J. Biol. Chem. 1989; 264: 7784-7787Abstract Full Text PDF PubMed Google Scholar) apparently active in renal acid secretion (9Alper S.L. Natale J. Gluck S. Lodish H.F. Brown D. Proc. Nat. Acad. Sci. (U. S. A.). 1989; 86: 5429-5433Crossref PubMed Scopus (332) Google Scholar). The AE2 gene encodes at least one polypeptide, which is widely distributed among various tissues and cultured cell lines(10Alper S.L. Kopito R.R. Libresco S.M. Lodish H.F. J. Biol. Chem. 1988; 263: 17092-17099Abstract Full Text PDF PubMed Google Scholar, 11Kudrycki K.E. Newman P.R. Shull G.E. J. Biol. Chem. 1990; 265: 462-471Abstract Full Text PDF PubMed Google Scholar) where it may mediate pHi regulation(12Jiang L. Stuart-Tilley A. Parkash J. Alper S.L. Am. J. Physiol. 1994; 267: C845-C856Crossref PubMed Google Scholar, 13Humphreys B.D. Jiang L. Chernova M.N. Alper S.L. Am. J. Physiol. 1994; 267: C1295-C1307Crossref PubMed Google Scholar), and/or volume regulation(14Humphreys B.D. Jiang L. Chernova M.N. Alper S.L. Am. J. Physiol. Cell Physiol. 1995; 37: C201-C209Crossref Google Scholar). The AE3 gene encodes at least two alternate transmembrane polypeptides with differing N termini. One was first cloned from brain and is termed the “brain” isoform(11Kudrycki K.E. Newman P.R. Shull G.E. J. Biol. Chem. 1990; 265: 462-471Abstract Full Text PDF PubMed Google Scholar, 15Kopito R.R. Lee B.S. Simmons D.M. Lindsey A.E. Morgans C.W. Schneider K. Cell. 1989; 59: 927-937Abstract Full Text PDF PubMed Scopus (204) Google Scholar, 16Yannoukakos D. Stuart-Tilley A. Fernandez H.A. Alper S.L. 1994; PubMed Scopus Google Scholar), the was cloned from and is termed the D. Stuart-Tilley A. Fernandez H.A. Alper S.L. 1994; PubMed Scopus Google Scholar, K.E. Shull G.E. J. Biol. Chem. 267: Full Text PDF PubMed Google Scholar). In addition, mRNA encoding a the transmembrane has been C.W. Kopito R.R. J. Cell Sci. Google Scholar). is known all HCO−3;/Cl− exchangers are members of the AE or this the of HCO−3;/Cl− exchange in all cell where it has been examined of the of the AE by HCO−3;/Cl− exchange has in various cell and by expressed AE HCO−3;/Cl− exchange is above a pHi which is J.M. Biggers J.D. Lechene C. J. Biol. Chem. 1991; 266: 17212-17217Abstract Full Text PDF PubMed Google Scholar, Brown J. Biol. Chem. 1988; 263: Full Text PDF PubMed Google Scholar, B.S. Kopito R.R. J. Biol. Chem. 1991; 266: Full Text PDF PubMed Google Scholar, K. J. Biol. Chem. Full Text PDF PubMed Google Scholar, S. K. J. Cell Biol. PubMed Scopus Google Scholar). be by of the L. Stuart-Tilley A. Parkash J. Alper S.L. Am. J. Physiol. 1994; 267: C845-C856Crossref PubMed Google Scholar, S. K. J. Cell Biol. PubMed Scopus Google Scholar). The activity is by stilbene such as DIDS, in the and an Cl− and Cl− for the and the Km for both is in the range of HCO−3;/Cl− exchange activity has been in the two-cell mouse the of this HCO−3;/Cl− a for HCO−3;/Cl− exchange activity in early development has been In addition, there has been no the or of HCO−3;/Cl− exchange activity in stages of preimplantation The
Zhao et al. (Sun,) studied this question.