The Low CO2-Inducible 36-Kilodalton Protein Is Localized to the Chloroplast Envelope of Chlamydomonas reinhardtii

Lack of the Rhesus protein Rh1 impairs growth of the green alga Chlamydomonas reinhardtii at high CO 2

“…These include genes coding for a periplasmic carbonic anhydrase Cah1 (36,38), the mitochondrial carbonic anhydrase mtCA (32,45), and the chloroplast envelope protein LIP-36 (33,46). We have found that these genes are also highly expressed when the two parental strains that we tested, 4Aϩ and CC125, are grown on acetate and bubbled with air (Fig.…”

“…When grown on acetate, they express three proteins involved in the CCM poorly, whereas parental strains express them well. Like parental strains, the rh1 RNAi lines express these three proteins, Cah1, mtCA, and LIP-36 (32,33,36,38,45,46), well when grown in air, indicating that they can sense the absence of high CO 2 . The failure of rh1 RNAi lines to express the CCM-associated proteins on acetate is parsimoniously explained if the small amounts of Rh1 protein present in parental strains increase leakage of CO 2 generated from acetate and hence contribute to a condition of internal CO 2 limitation.…”

Discovery of an algal mitochondrial carbonic anhydrase: molecular cloning and characterization of a low-CO2-induced polypeptide in Chlamydomonas reinhardtii.

“…One of these, a 37-kDa polypeptide, has been identified as an extracellular a-CA (12,13). Another one has been localized to the chloroplast envelope (14), but the function of that 36-kDa polypeptide is not known. Recently, Chen et al (15) reported that the gene encoding alanine aminotransferase is induced in low CO2 and codes for a 55-kDa polypeptide.…”

Insertional Mutants of Chlamydomonas reinhardtii That Require Elevated CO2 for Survival

“…C. reinhardtii and other aquatic photosynthetic organisms have a genetic program to allow them to acclimate to low CO 2 . This acclimation includes induction of a CO 2 -concentrating mechanism (CCM) that allows the cells to acquire CO 2 efficiently by increasing the CO 2 concentration around Rubisco under limiting CO 2 conditions (Badger et al, 1980; for review, see Spalding, 1998; Kaplan and Reinhold, 1999).Along with the induction of the CCM, C. reinhardtii shows adaptive changes to limiting CO 2 conditions, such as changes in cell organization (Geraghty and Spalding, 1996), increased photorespiratory enzyme activity , induction of periplasmic carbonic anhydrase (CA) (pCA1, encoded by the Cah1 gene; Fujiwara et al, 1990; Fukuzawa et al, 1990; Ishida et al, 1993), mitochondrial CA (mtCA, encoded by the Mca1 and Mca2 genes; Eriksson et al, 1996; Geraghty and Spalding, 1996), and putative chloroplast carrier protein (Ccp, encoded by the Ccp1 and Ccp2 genes; Geraghty et al, 1990;Ramazanov et al, 1993; Chen et al, 1997), and transient down-regulation in the synthesis of Rubisco (Coleman and Grossman, 1984;Winder et al, 1992).The signal for acclimation to limiting CO 2 in C. reinhardtii is unidentified. It is not known how they sense a change of CO 2 availability, whether by CO 2 concentration directly or indirectly via a cellular process such as carbohydrate metabolism.…”

“…Along with the induction of the CCM, C. reinhardtii shows adaptive changes to limiting CO 2 conditions, such as changes in cell organization (Geraghty and Spalding, 1996), increased photorespiratory enzyme activity , induction of periplasmic carbonic anhydrase (CA) (pCA1, encoded by the Cah1 gene; Fujiwara et al, 1990; Fukuzawa et al, 1990; Ishida et al, 1993), mitochondrial CA (mtCA, encoded by the Mca1 and Mca2 genes; Eriksson et al, 1996; Geraghty and Spalding, 1996), and putative chloroplast carrier protein (Ccp, encoded by the Ccp1 and Ccp2 genes; Geraghty et al, 1990;Ramazanov et al, 1993; Chen et al, 1997), and transient down-regulation in the synthesis of Rubisco (Coleman and Grossman, 1984;Winder et al, 1992).…”