human-PNLIPRP1

The finished sequence of human chromosome 10 comprises a total of 131,666,441 base pairs. It represents 99.4% of the euchromatic DNA and includes one megabase of heterochromatic sequence within the pericentromeric region of the short and long arm of the chromosome. Sequence annotation revealed 1,357 genes, of which 816 are protein coding, and 430 are pseudogenes. We observed widespread occurrence of overlapping coding genes (either strand) and identified 67 antisense transcripts. Our analysis suggests that both inter- and intrachromosomal segmental duplications have impacted on the gene count on chromosome 10. Multispecies comparative analysis indicated that we can readily annotate the protein-coding genes with current resources. We estimate that over 95% of all coding exons were identified in this study. Assessment of single base changes between the human chromosome 10 and chimpanzee sequence revealed nonsense mutations in only 21 coding genes with respect to the human sequence.

Pancreatic lipase-related protein 1 (PLRP1) was purified from human, canine, porcine and rat pancreatic juices. The four PLRP1s were identified using microsequencing methods after performing gel filtration on Ultrogel AcA-54 followed by chromatography on Heparin-Sepharose cation-exchanger. Polyclonal antibodies specific to human PLRP1 (HPLRP1) were raised in the rabbit using a synthetic decapeptide from HPLRP1. The results of Western blotting analysis showed that these antibodies recognized native HPLRP1 and recombinant HPLRP1 produced by insect cells, and cross-reacted only with rat PLRP1 (RPLRP1). No significant lipolytic activity was observed with native canine PLRP1 and recombinant HPLRP1 on various glycerides, phospholipid and vitamin esters, or on cholesterol esters. It was established for the first time that this protein is secreted in variable amounts by the adult exocrine pancreas of several species.

We have isolated cDNAs coding for two novel human pancreatic lipase (hPL)-related human proteins, referred to as hPL-related proteins 1 and 2 (hPLRP1 and hPLRP2) and for hPL. The two novel proteins show an amino acid sequence identity to hPL of 68 and 65% for hPLRP1 and 2, respectively. All three proteins are secreted into the medium after transfection of COS cells with the corresponding cDNAs. The size of the three expressed proteins is similar and ranges between 45 and 50 kDa. The expressed hPLRP2 shows a lipolytic activity that is, however, in contrast to that of hPL only marginally dependent on the presence of colipase, whereas hPLRP1 shows no activity in this assay. A Northern analysis of normal human pancreas mRNA shows that the expression levels of hPLRP1 and hPLRP2 are about 4-fold and 24-fold lower, respectively, than that of hPL. hPLRP2 is, additionally, most closely related to a lipase reported to be expressed in mouse T-cells. A comparison of the sequences of the three proteins with sequences described as pancreatic lipases of other animal species shows three subfamilies of closer kinship. This suggests that the two novel proteins also exist in other species and that some of the sequences reported to be pancreatic lipase might more likely be the orthologues of hPLRP1 or hPLRP2 in those species.

The finished sequence of human chromosome 10 comprises a total of 131,666,441 base pairs. It represents 99.4% of the euchromatic DNA and includes one megabase of heterochromatic sequence within the pericentromeric region of the short and long arm of the chromosome. Sequence annotation revealed 1,357 genes, of which 816 are protein coding, and 430 are pseudogenes. We observed widespread occurrence of overlapping coding genes (either strand) and identified 67 antisense transcripts. Our analysis suggests that both inter- and intrachromosomal segmental duplications have impacted on the gene count on chromosome 10. Multispecies comparative analysis indicated that we can readily annotate the protein-coding genes with current resources. We estimate that over 95% of all coding exons were identified in this study. Assessment of single base changes between the human chromosome 10 and chimpanzee sequence revealed nonsense mutations in only 21 coding genes with respect to the human sequence.

Pancreatic lipase-related protein 1 (PLRP1) was purified from human, canine, porcine and rat pancreatic juices. The four PLRP1s were identified using microsequencing methods after performing gel filtration on Ultrogel AcA-54 followed by chromatography on Heparin-Sepharose cation-exchanger. Polyclonal antibodies specific to human PLRP1 (HPLRP1) were raised in the rabbit using a synthetic decapeptide from HPLRP1. The results of Western blotting analysis showed that these antibodies recognized native HPLRP1 and recombinant HPLRP1 produced by insect cells, and cross-reacted only with rat PLRP1 (RPLRP1). No significant lipolytic activity was observed with native canine PLRP1 and recombinant HPLRP1 on various glycerides, phospholipid and vitamin esters, or on cholesterol esters. It was established for the first time that this protein is secreted in variable amounts by the adult exocrine pancreas of several species.

We have isolated cDNAs coding for two novel human pancreatic lipase (hPL)-related human proteins, referred to as hPL-related proteins 1 and 2 (hPLRP1 and hPLRP2) and for hPL. The two novel proteins show an amino acid sequence identity to hPL of 68 and 65% for hPLRP1 and 2, respectively. All three proteins are secreted into the medium after transfection of COS cells with the corresponding cDNAs. The size of the three expressed proteins is similar and ranges between 45 and 50 kDa. The expressed hPLRP2 shows a lipolytic activity that is, however, in contrast to that of hPL only marginally dependent on the presence of colipase, whereas hPLRP1 shows no activity in this assay. A Northern analysis of normal human pancreas mRNA shows that the expression levels of hPLRP1 and hPLRP2 are about 4-fold and 24-fold lower, respectively, than that of hPL. hPLRP2 is, additionally, most closely related to a lipase reported to be expressed in mouse T-cells. A comparison of the sequences of the three proteins with sequences described as pancreatic lipases of other animal species shows three subfamilies of closer kinship. This suggests that the two novel proteins also exist in other species and that some of the sequences reported to be pancreatic lipase might more likely be the orthologues of hPLRP1 or hPLRP2 in those species.

A 5 1/2-year-old boy is reported with congenital lipase deficiency and the presence of colipase. He presented with greasy-oily stools since infancy, but growth and development have been normal. No other cause for exocrine pancreatic insufficiency could be found. Intraluminal (jejunal) fat digestion was defective, but some hydrolytic products of dietary long-chain triglyceride were present. The di- and monoglycerides were probably generated by pregastric lipases, although this was not measured directly. Amylase activity was depressed to some extent, a finding which could not be explained. Our studies do not clarify the issue of whether or not the absence of pancreatic lipase is explained as an inherited defect of lipase synthesis, or if it was acquired in utero or in the early postnatal period.