02419nas a2200253   4500008004100000022001400041245015400055210006900209260000800278300001100286490000800297520148800305653002501793653002901818653003501847653003101882653002501913100001701938700002001955700002401975700001801999700002002017856012802037       2021                        eng d  a1369-703X00aCloning and expression of antibody fragment (Fab) I: effect of expression construct and induction strategies on light and heavy chain gene expression0 aCloning and expression of antibody fragment Fab I effect of expr  cDEC  a1081890 v1763 aDual promoter expression constructs offer time and cost-effective alternatives to produce multi-domain proteins like antibody fragments. This investigation is focused on understanding the effect of expression construct (dual promoter vs. co-transformation strategy), codon optimization, and induction strategies on yield and expression stoichiometry of LC and HC genes of antibody fragment at shake-flask and bioreactor scale. rHu biosimilar Ranibizumab was selected as a model protein for the study. Expression stoichiometry of HC and LC gene at mRNA level was studied using RTqPCR, whereas protein expression level was studied quantitatively using RP-HPLC and SDS-PAGE analysis. In the case of dual promoter expression construct, it was observed that LC gene cloned in the MCS1 of the duet vectors has > 2-fold expression than the HC gene, cloned in the MCS2. Transcript abundance profile of the HC and LC genes determined at different time intervals post-induction shows a difference in the gene expression at the transcriptional level. Comparative analysis of dual promoter and co-transformation strategy shows better stoichiometry in co-transformation (1:1.3), whereas higher protein yield in a dual expression system (>2.4 fold). The use of lactose and galactose as inducers show higher Fab yield of 2.30 +/- 0.03 g/L and 2.81 +/- 0.06 g/L with expression stoichiometry of 1:1.9 and 1:2 (HC: LC) respectively than IPTG-based induction with a protein yield of 1.40 +/- 0.02 g/L.10aDual promoter vector10aExpression stoichiometry10aHigh cell density fermentation10arHu biosimilar Ranibizumab10aTranscript abundance1 aMehta, Deepa1 aChirmade, Tejas1 aTungekar, Aatir, A.1 aGani, Kayanat1 aBhambure, Rahul  uhttps://library.ncl.res.in/content/cloning-and-expression-antibody-fragment-fab-i-effect-expression-construct-and-induction